644513806160 has 80 divisors (see below), whose sum is σ = 1712691618816. Its totient is φ = 220959857664.

The previous prime is 644513806159. The next prime is 644513806199. The reversal of 644513806160 is 61608315446.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9445124 + ... + 9513116.

Almost surely, 2^644513806160 is an apocalyptic number.

It is an amenable number.

644513806160 is an abundant number, since it is smaller than the sum of its proper divisors (1068177812656).

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

644513806160 is a wasteful number, since it uses less digits than its factorization.

644513806160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84940 (or 84934 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 44.

The spelling of 644513806160 in words is "six hundred forty-four billion, five hundred thirteen million, eight hundred six thousand, one hundred sixty".