644603046564 has 12 divisors (see below), whose sum is σ = 1504073775344. Its totient is φ = 214867682184.

The previous prime is 644603046517. The next prime is 644603046617. The reversal of 644603046564 is 465640306446.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26858460262 + ... + 26858460285.

Almost surely, 2^644603046564 is an apocalyptic number.

It is an amenable number.

644603046564 is an abundant number, since it is smaller than the sum of its proper divisors (859470728780).

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

644603046564 is a wasteful number, since it uses less digits than its factorization.

644603046564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53716920554 (or 53716920552 counting only the distinct ones).

The product of its (nonzero) digits is 4976640, while the sum is 48.

The spelling of 644603046564 in words is "six hundred forty-four billion, six hundred three million, forty-six thousand, five hundred sixty-four".