# 290 (number)

290 (two hundred [and] ninety) is the natural number following 289 and preceding 291.

 ← 289 290 291 →
Cardinaltwo hundred ninety
Ordinal290th
(two hundred ninetieth)
Factorization2 × 5 × 29
Greek numeralΣϞ´
Roman numeralCCXC
Binary1001000102
Ternary1012023
Octal4428
Duodecimal20212

## 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]

## 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

1. ^ "Sloane's A005282 : Mian-Chowla sequence". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-28.