664568322520 has 16 divisors (see below), whose sum is σ = 1495278725760. Its totient is φ = 265827328992.

The previous prime is 664568322449. The next prime is 664568322553. The reversal of 664568322520 is 25223865466.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8307103992 + ... + 8307104071.

It is an arithmetic number, because the mean of its divisors is an integer number (93454920360).

Almost surely, 2^664568322520 is an apocalyptic number.

It is an amenable number.

664568322520 is an abundant number, since it is smaller than the sum of its proper divisors (830710403240).

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

664568322520 is a wasteful number, since it uses less digits than its factorization.

664568322520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16614208074 (or 16614208070 counting only the distinct ones).

The product of its (nonzero) digits is 4147200, while the sum is 49.

The spelling of 664568322520 in words is "six hundred sixty-four billion, five hundred sixty-eight million, three hundred twenty-two thousand, five hundred twenty".