656139231 has 32 divisors (see below), whose sum is σ = 1067616000. Its totient is φ = 394964640.

The previous prime is 656139229. The next prime is 656139251. The reversal of 656139231 is 132931656.

656139231 is a `hidden beast` number, since 6 + 5 + 613 + 9 + 2 + 31 = 666.

It is not a de Polignac number, because 656139231 - 2¹ = 656139229 is a prime.

It is a super-2 number, since 2×656139231² = 861037380914542722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656139251) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36840 + ... + 51666.

It is an arithmetic number, because the mean of its divisors is an integer number (33363000).

Almost surely, 2^656139231 is an apocalyptic number.

656139231 is a deficient number, since it is larger than the sum of its proper divisors (411476769).

656139231 is a wasteful number, since it uses less digits than its factorization.

656139231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14996 (or 14990 counting only the distinct ones).

The product of its digits is 29160, while the sum is 36.

The square root of 656139231 is about 25615.2148341567. The cubic root of 656139231 is about 868.9577650107.

The spelling of 656139231 in words is "six hundred fifty-six million, one hundred thirty-nine thousand, two hundred thirty-one".