290 (number)

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290 (two hundred [and] ninety) is the natural number following 289 and preceding 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.

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 not be obtained as the sum of any two previous terms in the sequence.^[1]

See also the Bhargava–Hanke 290 theorem.

In other fields[]

• "290" was the shipyard number of the CSS Alabama

See also the year 290.

Integers from 291 to 299[]

291[]

291 = 3·97, a semiprime.

292[]

292 = 2²·73, noncototient, untouchable number. The continued fraction representation of ${\displaystyle \pi }$ 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 ${\displaystyle \pi }$, repdigit in base 8 (444).

293[]

293 is prime, Sophie Germain prime, Chen prime, Irregular prime, Eisenstein prime with no imaginary part, strictly non-palindromic number. For 293 cells in cell biology, see HEK cell.

294[]

294 = 2·3·7², unique period in base 10

295[]

295 = 5·59, also, the numerical designation of seven circumferential or half-circumferential routes of Interstate 95 in the United States.

296[]

296 = 2³·37, unique period in base 2

297[]

297 = 3³·11, number of integer partitions of 17, decagonal number, Kaprekar number

298[]

298 = 2·149, nontotient, noncototient

299[]

299 = 13·23, highly cototient number, self number, the twelfth cake number

References[]