290 (number)

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 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.

291 to 299

291

Two hundred [and] ninety-one 291 = 3·97, a semiprime.

292

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).

293

Two hundred [and] ninety-three 293 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

• Two hundred [and] ninety-four 294 = 2·3·7², unique period in base 10
• The fifth edition of The Organon of the Healing Art contained 294 aphorisms.

295

Two hundred [and] ninety-five 295 = 5·59, also, the numerical designation of seven circumfrental or half-circumfrental routes of Interstate 95 in the United States.

296

Two hundred [and] ninety-six 296 = 2³·37, unique period in base 2

297

Two hundred [and] ninety-seven 297 = 3³·11, number of integer partitions of 17, decagonal number, Kaprekar number

298

Two hundred [and] ninety-eight 298 = 2·149, nontotient, noncototient

299

Two hundred [and] ninety-nine 299 = 13·23, highly cototient number, self number, the twelfth cake number

References