251291 has 2 divisors, whose sum is σ = 251292. Its totient is φ = 251290.

The previous prime is 251287. The next prime is 251297. The reversal of 251291 is 192152.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 251291 - 2² = 251287 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (251297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125645 + 125646.

It is an arithmetic number, because the mean of its divisors is an integer number (125646).

2²⁵¹²⁹¹ is an apocalyptic number.

251291 is a deficient number, since it is larger than the sum of its proper divisors (1).

251291 is an equidigital number, since it uses as much as digits as its factorization.

251291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 180, while the sum is 20.

The square root of 251291 is about 501.2893376085. The cubic root of 251291 is about 63.1043035769.

The spelling of 251291 in words is "two hundred fifty-one thousand, two hundred ninety-one".