290 (number)
Encyclopedia : 2 : 29 : 290 : 290 (number)
290 is the natural number after 289 and before 291.
| |
| Ordinal | two hundred [and] nineieth |
| Cardinal | two hundred [and] ninety |
| Factorization | [2 \cdot 5 \cdot 29] |
| Roman numeral | CCXC |
| Binary | 100100010 |
| Hexadecimal | 122 |
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.
In other fields
There are four Interstate 290s in the United States.
See also the year 290.
291 to 299
Two hundred [and] ninety-one 291 = 3·97Two 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
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