800 (number)

← 799 800 801 →
List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	eight hundred
Ordinal	800th (eight hundredth)
Factorization	25× 52
Roman numeral	DCCC
Binary	11001000002
Ternary	10021223
Quaternary	302004
Quinary	112005
Senary	34126
Octal	14408
Duodecimal	56812
Hexadecimal	32016
Vigesimal	20020
Base 36	M836

800 (eight hundred) is the natural number following 799 and preceding 801.

It is the sum of four consecutive primes (193 + 197 + 199 + 211). It is a Harshad number.

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801 = 3² × 89, Harshad number

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802 = 2 × 401, sum of eight consecutive primes (83 + 89 + 97 + 101 + 103 + 107 + 109 + 113), nontotient, happy number

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803 = 11 × 73, sum of three consecutive primes (263 + 269 + 271), sum of nine consecutive primes (71 + 73 + 79 + 83 + 89 + 97 + 101 + 103 + 107), Harshad number

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804 = 2² × 3 × 67, nontotient, Harshad number

• "The 804" is a local nickname for the Greater Richmond Region of the U.S. state of Virginia, derived from its telephone area code (although the area code covers a larger area).

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805 = 5 × 7 × 23

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806 = 2 × 13 × 31, sphenic number, nontotient, totient sum for first 51 integers, happy number

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807 = 3 × 269

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808 = 2³ × 101, strobogrammatic number^[1]

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809 prime number, Sophie Germain prime,^[2] Chen prime, Eisenstein prime with no imaginary part

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810 = 2 × 3⁴ × 5, Harshad number

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811 prime number, sum of five consecutive primes (151 + 157 + 163 + 167 + 173), Chen prime, happy number, the Mertens function of 811 returns 0

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812 = 2² × 7 × 29, pronic number,^[3] the Mertens function of 812 returns 0

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813 = 3 × 271

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814 = 2 × 11 × 37, sphenic number, the Mertens function of 814 returns 0, nontotient

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815 = 5 × 163

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816 = 2⁴ × 3 × 17, tetrahedral number,^[4] Padovan number,^[5] Zuckerman number

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817 = 19 × 43, sum of three consecutive primes (269 + 271 + 277), centered hexagonal number^[6]

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818 = 2 × 409, nontotient, strobogrammatic number^[1]

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819 = 3² × 7 × 13, square pyramidal number^[7]

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820 = 2² × 5 × 41, triangular number,^[8] Harshad number, happy number, repdigit (1111) in base 9

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821 prime number, twin prime, Eisenstein prime with no imaginary part, prime quadruplet with 823, 827, 829

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822 = 2 × 3 × 137, sum of twelve consecutive primes (43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89 + 97), sphenic number, member of the Mian–Chowla sequence^[9]

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823 prime number, twin prime, the Mertens function of 823 returns 0, prime quadruplet with 821, 827, 829

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824 = 2³ × 103, sum of ten consecutive primes (61 + 67 + 71 + 73 + 79 + 83 + 89 + 97 + 101 + 103), the Mertens function of 824 returns 0, nontotient

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825 = 3 × 5² × 11, Smith number,^[10] the Mertens function of 825 returns 0, Harshad number

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826 = 2 × 7 × 59, sphenic number

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827 prime number, twin prime, part of prime quadruplet with {821, 823, 829}, sum of seven consecutive primes (103 + 107 + 109 + 113 + 127 + 131 + 137), Chen prime, Eisenstein prime with no imaginary part, strictly non-palindromic number^[11]

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828 = 2² × 3² × 23, Harshad number

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829 prime number, twin prime, part of prime quadruplet with {827, 823, 821}, sum of three consecutive primes (271 + 277 + 281), Chen prime

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830 = 2 × 5 × 83, sphenic number, sum of four consecutive primes (197 + 199 + 211 + 223), nontotient, totient sum for first 52 integers

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831 = 3 × 277

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832 = 2⁶ × 13, Harshad number

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833 = 7² × 17

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834 = 2 × 3 × 139, sphenic number, sum of six consecutive primes (127 + 131 + 137 + 139 + 149 + 151), nontotient

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835 = 5 × 167, Motzkin number^[12]

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836 = 2² × 11 × 19, weird number

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837 = 3³ × 31

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838 = 2 × 419

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839 prime number, safe prime,^[13] sum of five consecutive primes (157 + 163 + 167 + 173 + 179), Chen prime, Eisenstein prime with no imaginary part, highly cototient number^[14]

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840 = 2³ × 3 × 5 × 7, highly composite number,^[15] smallest numbers divisible by the numbers 1 to 8 (lowest common multiple of 1 to 8), sparsely totient number,^[16] Harshad number in base 2 through base 10

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841 = 29² = 20² + 21², sum of three consecutive primes (277 + 281 + 283), sum of nine consecutive primes (73 + 79 + 83 + 89 + 97 + 101 + 103 + 107 + 109), centered square number,^[17] centered heptagonal number,^[18] centered octagonal number^[19]

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842 = 2 × 421, nontotient

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843 = 3 × 281, Lucas number^[20]

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844 = 2² × 211, nontotient

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845 = 5 × 13²

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846 = 2 × 3² × 47, sum of eight consecutive primes (89 + 97 + 101 + 103 + 107 + 109 + 113 + 127), nontotient, Harshad number

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847 = 7 × 11², happy number

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848 = 2⁴ × 53

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849 = 3 × 283, the Mertens function of 849 returns 0

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850 = 2 × 5² × 17, the Mertens function of 850 returns 0, nontotient, the maximum possible Fair Isaac credit score, country calling code for North Korea

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851 = 23 × 37

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852 = 2² × 3 × 71, pentagonal number,^[21] Smith number^[10]

• country calling code for Hong Kong

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853 prime number, Perrin number,^[22] the Mertens function of 853 returns 0, average of first 853 prime numbers is an integer (sequence A045345 in the OEIS), strictly non-palindromic number, number of connected graphs with 7 nodes

• country calling code for Macau

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854 = 2 × 7 × 61, nontotient

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855 = 3² × 5 × 19, decagonal number,^[23] centered cube number^[24]

• country calling code for Cambodia

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856 = 2³ × 107, nonagonal number,^[25] centered pentagonal number,^[26] happy number

• country calling code for Laos

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857 prime number, sum of three consecutive primes (281 + 283 + 293), Chen prime, Eisenstein prime with no imaginary part

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858 = 2 × 3 × 11 × 13, Giuga number^[27]

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859 prime number

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860 = 2² × 5 × 43, sum of four consecutive primes (199 + 211 + 223 + 227)

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861 = 3 × 7 × 41, sphenic number, triangular number,^[8] hexagonal number,^[28] Smith number^[10]

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862 = 2 × 431

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863 prime number, safe prime,^[13] sum of five consecutive primes (163 + 167 + 173 + 179 + 181), sum of seven consecutive primes (107 + 109 + 113 + 127 + 131 + 137 + 139), Chen prime, Eisenstein prime with no imaginary part

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864 = 2⁵ × 3³, sum of a twin prime (431 + 433), sum of six consecutive primes (131 + 137 + 139 + 149 + 151 + 157), Harshad number

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865 = 5 × 173,

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866 = 2 × 433, nontotient

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867 = 3 × 17²

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868 = 2² × 7 × 31, nontotient

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869 = 11 × 79, the Mertens function of 869 returns 0

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870 = 2 × 3 × 5 × 29, sum of ten consecutive primes (67 + 71 + 73 + 79 + 83 + 89 + 97 + 101 + 103 + 107), pronic number,^[3] nontotient, sparsely totient number,^[16] Harshad number

This number is the magic constant of n×n normal magic square and n-queens problem for n = 12.

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871 = 13 × 67

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872 = 2³ × 109, nontotient

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873 = 3² × 97, sum of the first six factorials from 1

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874 = 2 × 19 × 23, sum of the first twenty-three primes, sum of the first seven factorials from 0, nontotient, Harshad number, happy number

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875 = 5³ × 7

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876 = 2² × 3 × 73

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877 prime number, Bell number,^[29] Chen prime, the Mertens function of 877 returns 0, strictly non-palindromic number.^[11]

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878 = 2 × 439, nontotient

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879 = 3 × 293

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880 = 2⁴ × 5 × 11, Harshad number; 148-gonal number; the number of n×n magic squares for n = 4.

• country calling code for Bangladesh

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881 prime number, twin prime, sum of nine consecutive primes (79 + 83 + 89 + 97 + 101 + 103 + 107 + 109 + 113), Chen prime, Eisenstein prime with no imaginary part

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882 = 2 × 3² × 7², Harshad number, totient sum for first 53 integers

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883 prime number, twin prime, sum of three consecutive primes (283 + 293 + 307), the Mertens function of 883 returns 0, happy number

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884 = 2² × 13 × 17, the Mertens function of 884 returns 0

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885 = 3 × 5 × 59, sphenic number

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886 = 2 × 443, the Mertens function of 886 returns 0

• country calling code for Taiwan

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887 prime number followed by primal gap of 20, safe prime,^[13] Chen prime, Eisenstein prime with no imaginary part

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888 = 2³ × 3 × 37, sum of eight consecutive primes (97 + 101 + 103 + 107 + 109 + 113 + 127 + 131), Harshad number, strobogrammatic number^[1]

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889 = 7 × 127, the Mertens function of 889 returns 0

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890 = 2 × 5 × 89, sphenic number, sum of four consecutive primes (211 + 223 + 227 + 229), nontotient

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891 = 3⁴ × 11, sum of five consecutive primes (167 + 173 + 179 + 181 + 191), octahedral number

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892 = 2² × 223, nontotient

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893 = 19 × 47, the Mertens function of 893 returns 0

• Considered an unlucky number in Japan, because its digits read sequentially are the literal translation of yakuza.

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894 = 2 × 3 × 149, sphenic number, nontotient

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895 = 5 × 179, Smith number,^[10] Woodall number,^[30] the Mertens function of 895 returns 0

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896 = 2⁷ × 7, sum of six consecutive primes (137 + 139 + 149 + 151 + 157 + 163), the Mertens function of 896 returns 0

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897 = 3 × 13 × 23, sphenic number

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898 = 2 × 449, the Mertens function of 898 returns 0, nontotient

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899 = 29 × 31, happy number

References