639476920 has 64 divisors (see below), whose sum is σ = 1555552800. Its totient is φ = 235768320.

The previous prime is 639476917. The next prime is 639476953. The reversal of 639476920 is 29674936.

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, 16750 + ... + 39490.

Almost surely, 2^639476920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639476920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (777776400).

639476920 is an abundant number, since it is smaller than the sum of its proper divisors (916075880).

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

639476920 is a wasteful number, since it uses less digits than its factorization.

639476920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22808 (or 22804 counting only the distinct ones).

The product of its (nonzero) digits is 489888, while the sum is 46.

The square root of 639476920 is about 25287.8808918422. The cubic root of 639476920 is about 861.5390325006.

The spelling of 639476920 in words is "six hundred thirty-nine million, four hundred seventy-six thousand, nine hundred twenty".