Table of prime factors
The tables contain the prime factorization of the natural numbers from 1 to 1000.
When n is a prime number, the prime factorization is just n itself, written in bold below.
The number 1 is called a unit. It has no prime factors and is neither prime nor composite.
See also: Table of divisors (prime and non-prime divisors for 1 to 1000)
Properties
Many properties of a natural number n can be seen or directly computed from the prime factorization of n.
- The multiplicity of a prime factor p of n is the largest exponent m for which pm divides n. The tables show the multiplicity for each prime factor. If no exponent is written then the multiplicity is 1 (since p = p1). The multiplicity of a prime which does not divide n may be called 0 or may be considered undefined.
- Ω(n), the big Omega function, is the number of prime factors of n counted with multiplicity (so it is the sum of all prime factor multiplicities).
- A prime number has Ω(n) = 1. The first: 2, 3, 5, 7, 11 (sequence A000040 in OEIS). There are many special types of prime numbers.
- A composite number has Ω(n) > 1. The first: 4, 6, 8, 9, 10 (sequence A002808 in OEIS). All numbers above 1 are either prime or composite. 1 is neither.
- A semiprime has Ω(n) = 2 (so it is composite). The first: 4, 6, 9, 10, 14 (sequence A001358 in OEIS).
- A k-almost prime (for a natural number k) has Ω(n) = k (so it is composite if k > 1).
- An even number has the prime factor 2. The first: 2, 4, 6, 8, 10 (sequence A005843 in OEIS).
- An odd number does not have the prime factor 2. The first: 1, 3, 5, 7, 9 (sequence A005408 in OEIS). All integers are either even or odd.
- A square has even multiplicity for all prime factors (it is of the form a2 for some a). The first: 1, 4, 9, 16, 25 (sequence A000290 in OEIS).
- A cube has all multiplicities divisible by 3 (it is of the form a3 for some a). The first: 1, 8, 27, 64, 125 (sequence A000578 in OEIS).
- A perfect power has a common divisor m > 1 for all multiplicities (it is of the form am for some a > 1 and m > 1). The first: 4, 8, 9, 16, 25 (sequence A001597 in OEIS). 1 is sometimes included.
- A powerful number (also called squareful) has multiplicity above 1 for all prime factors. The first: 1, 4, 8, 9, 16 (sequence A001694 in OEIS).
- An Achilles number is powerful but not a perfect power. The first: 72, 108, 200, 288, 392 (sequence A052486 in OEIS).
- A square-free integer has no prime factor with multiplicity above 1. The first: 1, 2, 3, 5, 6 (sequence A005117 in OEIS)). A number where some but not all prime factors have multiplicity above 1 is neither square-free nor squareful.
- The Liouville function λ(n) is 1 if Ω(n) is even, and is -1 if Ω(n) is odd.
- The Möbius function μ(n) is 0 if n is not square-free. Otherwise μ(n) is 1 if Ω(n) is even, and is −1 if Ω(n) is odd.
- A sphenic number has Ω(n) = 3 and is square-free (so it is the product of 3 distinct primes). The first: 30, 42, 66, 70, 78 (sequence A007304 in OEIS).
- a0(n) is the sum of primes dividing n, counted with multiplicity. It is an additive function.
- A Ruth-Aaron pair is two consecutive numbers (x, x+1) with a0(x) = a0(x+1). The first (by x value): 5, 8, 15, 77, 125 (sequence A039752 in OEIS).
- A primorial x# is the product of all primes from 2 to x. The first: 2, 6, 30, 210, 2310 (sequence A002110 in OEIS). 1# = 1 is sometimes included.
- A factorial x! is the product of all numbers from 1 to x. The first: 1, 2, 6, 24, 120 (sequence A000142 in OEIS).
- A k-smooth number (for a natural number k) has largest prime factor ≤ k (so it is also j-smooth for any j > k).
- m is smoother than n if the largest prime factor of m is below the largest of n.
- A regular number has no prime factor above 5 (so it is 5-smooth). The first: 1, 2, 3, 4, 5, 6, 8 (sequence A051037 in OEIS).
- A k-powersmooth number has all pm ≤ k where p is a prime factor with multiplicity m.
- A frugal number has more digits than the number of digits in its prime factorization (when written like below tables with multiplicities above 1 as exponents). The first in decimal: 125, 128, 243, 256, 343 (sequence A046759 in OEIS).
- An equidigital number has the same number of digits as its prime factorization. The first in decimal: 1, 2, 3, 5, 7, 10 (sequence A046758 in OEIS).
- An extravagant number has fewer digits than its prime factorization. The first in decimal: 4, 6, 8, 9, 12 (sequence A046760 in OEIS).
- An economical number has been defined as a frugal number, but also as a number that is either frugal or equidigital.
- gcd(m, n) (greatest common divisor of m and n) is the product of all prime factors which are both in m and n (with the smallest multiplicity for m and n).
- m and n are coprime (also called relatively prime) if gcd(m, n) = 1 (meaning they have no common prime factor).
- lcm(m, n) (least common multiple of m and n) is the product of all prime factors of m or n (with the largest multiplicity for m or n).
- gcd(m, n) × lcm(m, n) = m × n. Finding the prime factors is often harder than to compute gcd and lcm with other algorithms which do not require known prime factorization.
- m is a divisor of n (also called m divides n, or n is divisible by m) if all prime factors of m have at least the same multiplicity in n.
The divisors of n are all products of some or all prime factors of n (including the empty product 1 of no prime factors). The number of divisors can be computed by increasing all multiplicities by 1 and then multiplying them. Divisors and properties related to divisors are shown in table of divisors.
1 to 100
If numbers are arranged in increasing columns of n numbers, then the prime factors of n will occur in the same row each time. The table columns have 20 = 22·5 numbers, so the prime factors 2 and 5 occur in fixed rows.
101 to 200
201 to 300
301 to 400
401 to 500
501 to 600
601 to 700
701 to 800
801 to 900
801 - 820
801 |
32·89 |
802 |
2·401 |
803 |
11·73 |
804 |
22·3·67 |
805 |
5·7·23 |
806 |
2·13·31 |
807 |
3·269 |
808 |
23·101 |
809 |
809 |
810 |
2·34·5 |
811 |
811 |
812 |
22·7·29 |
813 |
3·271 |
814 |
2·11·37 |
815 |
5·163 |
816 |
24·3·17 |
817 |
19·43 |
818 |
2·409 |
819 |
32·7·13 |
820 |
22·5·41 |
|
821 - 840
821 |
821 |
822 |
2·3·137 |
823 |
823 |
824 |
23·103 |
825 |
3·52·11 |
826 |
2·7·59 |
827 |
827 |
828 |
22·32·23 |
829 |
829 |
830 |
2·5·83 |
831 |
3·277 |
832 |
26·13 |
833 |
72·17 |
834 |
2·3·139 |
835 |
5·167 |
836 |
22·11·19 |
837 |
33·31 |
838 |
2·419 |
839 |
839 |
840 |
23·3·5·7 |
|
841 - 860
841 |
292 |
842 |
2·421 |
843 |
3·281 |
844 |
22·211 |
845 |
5·132 |
846 |
2·32·47 |
847 |
7·112 |
848 |
24·53 |
849 |
3·283 |
850 |
2·52·17 |
851 |
23·37 |
852 |
22·3·71 |
853 |
853 |
854 |
2·7·61 |
855 |
32·5·19 |
856 |
23·107 |
857 |
857 |
858 |
2·3·11·13 |
859 |
859 |
860 |
22·5·43 |
|
861 - 880
861 |
3·7·41 |
862 |
2·431 |
863 |
863 |
864 |
25·33 |
865 |
5·173 |
866 |
2·433 |
867 |
3·172 |
868 |
22·7·31 |
869 |
11·79 |
870 |
2·3·5·29 |
871 |
13·67 |
872 |
23·109 |
873 |
32·97 |
874 |
2·19·23 |
875 |
53·7 |
876 |
22·3·73 |
877 |
877 |
878 |
2·439 |
879 |
3·293 |
880 |
24·5·11 |
|
881 - 900
881 |
881 |
882 |
2·32·72 |
883 |
883 |
884 |
22·13·17 |
885 |
3·5·59 |
886 |
2·443 |
887 |
887 |
888 |
23·3·37 |
889 |
7·127 |
890 |
2·5·89 |
891 |
34·11 |
892 |
22·223 |
893 |
19·47 |
894 |
2·3·149 |
895 |
5·179 |
896 |
27·7 |
897 |
3·13·23 |
898 |
2·449 |
899 |
29·31 |
900 |
22·32·52 |
|
901 to 1000
901 - 920
901 |
17·53 |
902 |
2·11·41 |
903 |
3·7·43 |
904 |
23·113 |
905 |
5·181 |
906 |
2·3·151 |
907 |
907 |
908 |
22·227 |
909 |
32·101 |
910 |
2·5·7·13 |
911 |
911 |
912 |
24·3·19 |
913 |
11·83 |
914 |
2·457 |
915 |
3·5·61 |
916 |
22·229 |
917 |
7·131 |
918 |
2·33·17 |
919 |
919 |
920 |
23·5·23 |
|
921 - 940
921 |
3·307 |
922 |
2·461 |
923 |
13·71 |
924 |
22·3·7·11 |
925 |
52·37 |
926 |
2·463 |
927 |
32·103 |
928 |
25·29 |
929 |
929 |
930 |
2·3·5·31 |
931 |
72·19 |
932 |
22·233 |
933 |
3·311 |
934 |
2·467 |
935 |
5·11·17 |
936 |
23·32·13 |
937 |
937 |
938 |
2·7·67 |
939 |
3·313 |
940 |
22·5·47 |
|
941 - 960
941 |
941 |
942 |
2·3·157 |
943 |
23·41 |
944 |
24·59 |
945 |
33·5·7 |
946 |
2·11·43 |
947 |
947 |
948 |
22·3·79 |
949 |
13·73 |
950 |
2·52·19 |
951 |
3·317 |
952 |
23·7·17 |
953 |
953 |
954 |
2·32·53 |
955 |
5·191 |
956 |
22·239 |
957 |
3·11·29 |
958 |
2·479 |
959 |
7·137 |
960 |
26·3·5 |
|
961 - 980
961 |
312 |
962 |
2·13·37 |
963 |
32·107 |
964 |
22·241 |
965 |
5·193 |
966 |
2·3·7·23 |
967 |
967 |
968 |
23·112 |
969 |
3·17·19 |
970 |
2·5·97 |
971 |
971 |
972 |
22·35 |
973 |
7·139 |
974 |
2·487 |
975 |
3·52·13 |
976 |
24·61 |
977 |
977 |
978 |
2·3·163 |
979 |
11·89 |
980 |
22·5·72 |
|
981 - 1000
981 |
32·109 |
982 |
2·491 |
983 |
983 |
984 |
23·3·41 |
985 |
5·197 |
986 |
2·17·29 |
987 |
3·7·47 |
988 |
22·13·19 |
989 |
23·43 |
990 |
2·32·5·11 |
991 |
991 |
992 |
25·31 |
993 |
3·331 |
994 |
2·7·71 |
995 |
5·199 |
996 |
22·3·83 |
997 |
997 |
998 |
2·499 |
999 |
33·37 |
1000 |
23·53 |
|