644076980 has 48 divisors (see below), whose sum is σ = 1372412160. Its totient is φ = 253870848.

The previous prime is 644076949. The next prime is 644077001. The reversal of 644076980 is 89670446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 866489 + ... + 867231.

It is an arithmetic number, because the mean of its divisors is an integer number (28591920).

Almost surely, 2^644076980 is an apocalyptic number.

It is an amenable number.

644076980 is an abundant number, since it is smaller than the sum of its proper divisors (728335180).

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

644076980 is a wasteful number, since it uses less digits than its factorization.

644076980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1328 (or 1326 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 44.

The square root of 644076980 is about 25378.6717540536. The cubic root of 644076980 is about 863.5999180054.

The spelling of 644076980 in words is "six hundred forty-four million, seventy-six thousand, nine hundred eighty".