644532653004564 has 12 divisors (see below), whose sum is σ = 1503909523677344. Its totient is φ = 214844217668184.

The previous prime is 644532653004529. The next prime is 644532653004719. The reversal of 644532653004564 is 465400356235446.

It is a tau number, because it is divible by the number of its divisors (12).

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 3 ways as a sum of consecutive naturals, for example, 26855527208512 + ... + 26855527208535.

Almost surely, 2^{644532653004564} is an apocalyptic number.

It is an amenable number.

644532653004564 is an abundant number, since it is smaller than the sum of its proper divisors (859376870672780).

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

644532653004564 is a wasteful number, since it uses less digits than its factorization.

644532653004564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53711054417054 (or 53711054417052 counting only the distinct ones).

The product of its (nonzero) digits is 124416000, while the sum is 57.

The spelling of 644532653004564 in words is "six hundred forty-four trillion, five hundred thirty-two billion, six hundred fifty-three million, four thousand, five hundred sixty-four".