644386984 has 16 divisors (see below), whose sum is σ = 1208797920. Its totient is φ = 322040880.

The previous prime is 644386891. The next prime is 644386991. The reversal of 644386984 is 489683446.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12 + ... + 35899.

It is an arithmetic number, because the mean of its divisors is an integer number (75549870).

Almost surely, 2^644386984 is an apocalyptic number.

It is an amenable number.

644386984 is a deficient number, since it is larger than the sum of its proper divisors (564410936).

644386984 is a wasteful number, since it uses less digits than its factorization.

644386984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38160 (or 38156 counting only the distinct ones).

The product of its digits is 3981312, while the sum is 52.

The square root of 644386984 is about 25384.7785887527. The cubic root of 644386984 is about 863.7384503528.

The spelling of 644386984 in words is "six hundred forty-four million, three hundred eighty-six thousand, nine hundred eighty-four".