256621631 has 16 divisors (see below), whose sum is σ = 298114560. Its totient is φ = 216367200.

The previous prime is 256621577. The next prime is 256621633. The reversal of 256621631 is 136126652.

It is not a de Polignac number, because 256621631 - 2⁶ = 256621567 is a prime.

It is a super-2 number, since 2×256621631² = 131709322994200322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256621633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 111965 + ... + 114233.

It is an arithmetic number, because the mean of its divisors is an integer number (18632160).

Almost surely, 2^256621631 is an apocalyptic number.

256621631 is a deficient number, since it is larger than the sum of its proper divisors (41492929).

256621631 is a wasteful number, since it uses less digits than its factorization.

256621631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2534.

The product of its digits is 12960, while the sum is 32.

The square root of 256621631 is about 16019.4141902880. The cubic root of 256621631 is about 635.4739520717.

The spelling of 256621631 in words is "two hundred fifty-six million, six hundred twenty-one thousand, six hundred thirty-one".