664860307728 has 20 divisors (see below), whose sum is σ = 1717555795088. Its totient is φ = 221620102560.

The previous prime is 664860307697. The next prime is 664860307757. The reversal of 664860307728 is 827703068466.

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, 6925628158 + ... + 6925628253.

Almost surely, 2^664860307728 is an apocalyptic number.

It is an amenable number.

664860307728 is an abundant number, since it is smaller than the sum of its proper divisors (1052695487360).

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

664860307728 is a wasteful number, since it uses less digits than its factorization.

664860307728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13851256422 (or 13851256416 counting only the distinct ones).

The product of its (nonzero) digits is 16257024, while the sum is 57.

The spelling of 664860307728 in words is "six hundred sixty-four billion, eight hundred sixty million, three hundred seven thousand, seven hundred twenty-eight".