256131491 has 8 divisors (see below), whose sum is σ = 319332864. Its totient is φ = 199582920.

The previous prime is 256131487. The next prime is 256131493. The reversal of 256131491 is 194131652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 256131491 - 2² = 256131487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256131493) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1663115 + ... + 1663268.

It is an arithmetic number, because the mean of its divisors is an integer number (39916608).

Almost surely, 2^256131491 is an apocalyptic number.

256131491 is a deficient number, since it is larger than the sum of its proper divisors (63201373).

256131491 is a wasteful number, since it uses less digits than its factorization.

256131491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3326401.

The product of its digits is 6480, while the sum is 32.

The square root of 256131491 is about 16004.1085662401. The cubic root of 256131491 is about 635.0691151753.

The spelling of 256131491 in words is "two hundred fifty-six million, one hundred thirty-one thousand, four hundred ninety-one".