639381128 has 32 divisors (see below), whose sum is σ = 1231200000. Its totient is φ = 311176320.

The previous prime is 639381109. The next prime is 639381137. The reversal of 639381128 is 821183936.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37748 + ... + 51996.

It is an arithmetic number, because the mean of its divisors is an integer number (38475000).

Almost surely, 2^639381128 is an apocalyptic number.

It is an amenable number.

639381128 is a deficient number, since it is larger than the sum of its proper divisors (591818872).

639381128 is a wasteful number, since it uses less digits than its factorization.

639381128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14405 (or 14401 counting only the distinct ones).

The product of its digits is 62208, while the sum is 41.

The square root of 639381128 is about 25285.9867911063. The cubic root of 639381128 is about 861.4960115744.

The spelling of 639381128 in words is "six hundred thirty-nine million, three hundred eighty-one thousand, one hundred twenty-eight".