| Ordinal | two hundred [and] ninetieth |
| Cardinal | two hundred [and] ninety |
| Factorization |  |
| Roman numeral | CCXC |
| Binary | 100100010 |
| Hexadecimal | 122 |
290 (two hundred [and] ninety) is the natural number after 289 and before 291.
In mathematics
The product of three primes, 290 is a sphenic number, and the sum of four consecutive primes (67 + 71 + 73 + 79). The sum of the squares of the divisors of 17 is 290. If you multiply 5,2,and 29, you get 290.
Not only is it a nontotient and a noncototient, it is also an untouchable number.
290 is the 16th member of the Mian-Chowla sequence; it can't be obtained as the sum of any two previous terms in the sequence.
See also the Bhargava-Hanke 290 theorem.
In other fields
- "290" is one of Naoki Maeda's pseudonyms.
- "290" was the shipyard number of the CSS Alabama
See also the year 290.
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. For 293 cells in cell biology, see HEK cell.
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, the twelfth cake number
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