521664352056 has 32 divisors (see below), whose sum is σ = 1449067645200. Its totient is φ = 173888117280.

The previous prime is 521664351997. The next prime is 521664352133. The reversal of 521664352056 is 650253466125.

521664352056 is a `hidden beast` number, since 5 + 2 + 1 + 6 + 6 + 435 + 205 + 6 = 666.

It is a super-2 number, since 2×521664352056² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1207556155 + ... + 1207556586.

Almost surely, 2^521664352056 is an apocalyptic number.

It is an amenable number.

521664352056 is an abundant number, since it is smaller than the sum of its proper divisors (927403293144).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

521664352056 is a wasteful number, since it uses less digits than its factorization.

521664352056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2415112756 (or 2415112746 counting only the distinct ones).

The product of its (nonzero) digits is 1296000, while the sum is 45.

The spelling of 521664352056 in words is "five hundred twenty-one billion, six hundred sixty-four million, three hundred fifty-two thousand, fifty-six".