290 (number)
From Wikipedia, the free encyclopedia
| Ordinal | two hundred [and] nineieth |
| Cardinal | two hundred [and] ninety |
| Factorization |  |
| Roman numeral | CCXC |
| Binary | 100100010 |
| Hexadecimal | 122 |
290 is the natural number after 289 and before 291.
[edit] In mathematics
The product of three primes, 290 is a sphenic number, and the sum of four consecutive primes (67 + 71 + 73 + 79). The squares of the divisors of 17 is 290.
Not only is it a nontotient and a noncototient, it is also an untouchable number.
In a sieve like that for lucky numbers, but starting with the even numbers, 290 survives the sieving process.
See also Conway's 290 theorem.
[edit] In other fields
- There are four Interstate 290s in the United States.
- "290" is one of Naoki Maeda's pseudonyms.
See also the year 290.
[edit] 291 to 299
- Two hundred [and] ninety-one 291 = 3·97
- Two hundred [and] ninety-two 292 = 22·73, noncototient, untouchable number. The continued fraction representation of pi is [3; 7, 15, 1, 292, 1, 1, 1, 2...]; the convergent obtained by truncating before the surprisingly large term 292 yields the excellent rational approximation 355/113 to pi, repdigit in base 8 (444).
- Two hundred [and] ninety-three 293 prime, Sophie Germain prime, Chen prime, Eisenstein prime with no imaginary part, strictly non-palindromic number
- Two hundred [and] ninety-four 294 = 2·3·72
- Two hundred [and] ninety-five 295 = 5·59, also, the numerical designation of seven spur routes of Interstate 95 in the United States.
- Two hundred [and] ninety-six 296 = 23·37
- Two hundred [and] ninety-seven 297 = 33·11, decagonal number, Kaprekar number
- Two hundred [and] ninety-eight 298 = 2·149, nontotient, noncototient
- Two hundred [and] ninety-nine 299 = 13·23, highly cototient number, self number
