656328439881 has 81 divisors (see below), whose sum is σ = 1021608301077. Its totient is φ = 405977857920.

The previous prime is 656328439861. The next prime is 656328439883. The reversal of 656328439881 is 188934823656.

It is a happy number.

The square root of 656328439881 is 810141.

It is a perfect power (a square), and thus also a powerful number.

656328439881 is a `hidden beast` number, since 6 + 563 + 28 + 43 + 9 + 8 + 8 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 416702525625 + 239625914256 = 645525^2 + 489516^2 .

It is not a de Polignac number, because 656328439881 - 2⁵ = 656328439849 is a prime.

It is a super-2 number, since 2×656328439881² (a number of 24 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (656328439883) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 2816860141 + ... + 2816860373.

Almost surely, 2^656328439881 is an apocalyptic number.

656328439881 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

656328439881 is the 810141-st square number.

656328439881 is the 405071-st centered octagonal number.

It is an amenable number.

656328439881 is a deficient number, since it is larger than the sum of its proper divisors (365279861196).

656328439881 is an equidigital number, since it uses as much as digits as its factorization.

656328439881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 632 (or 316 counting only the distinct ones).

The product of its digits is 59719680, while the sum is 63.

It can be divided in two parts, 656328 and 439881, that added together give a square (1096209 = 1047²).

The spelling of 656328439881 in words is "six hundred fifty-six billion, three hundred twenty-eight million, four hundred thirty-nine thousand, eight hundred eighty-one".