664520215656 has 64 divisors (see below), whose sum is σ = 1823180244480. Its totient is φ = 200163942080.

The previous prime is 664520215561. The next prime is 664520215757. The reversal of 664520215656 is 656512025466.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7492206 + ... + 7580381.

It is an arithmetic number, because the mean of its divisors is an integer number (28487191320).

Almost surely, 2^664520215656 is an apocalyptic number.

664520215656 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

664520215656 is an abundant number, since it is smaller than the sum of its proper divisors (1158660028824).

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

664520215656 is a wasteful number, since it uses less digits than its factorization.

664520215656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15072774 (or 15072770 counting only the distinct ones).

The product of its (nonzero) digits is 2592000, while the sum is 48.

The spelling of 664520215656 in words is "six hundred sixty-four billion, five hundred twenty million, two hundred fifteen thousand, six hundred fifty-six".