639139472 has 20 divisors (see below), whose sum is σ = 1240716720. Its totient is φ = 318954528.

The previous prime is 639139453. The next prime is 639139477. The reversal of 639139472 is 274931936.

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (639139477) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 29822 + ... + 46557.

It is an arithmetic number, because the mean of its divisors is an integer number (62035836).

Almost surely, 2^639139472 is an apocalyptic number.

It is an amenable number.

639139472 is a deficient number, since it is larger than the sum of its proper divisors (601577248).

639139472 is a wasteful number, since it uses less digits than its factorization.

639139472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76910 (or 76904 counting only the distinct ones).

The product of its digits is 244944, while the sum is 44.

The square root of 639139472 is about 25281.2078825360. The cubic root of 639139472 is about 861.3874629041.

The spelling of 639139472 in words is "six hundred thirty-nine million, one hundred thirty-nine thousand, four hundred seventy-two".