639388138875 has 16 divisors (see below), whose sum is σ = 1063941863712. Its totient is φ = 341007007200.

The previous prime is 639388138849. The next prime is 639388138903. The reversal of 639388138875 is 578831883936.

It is not a de Polignac number, because 639388138875 - 2⁸ = 639388138619 is a prime.

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, 852517144 + ... + 852517893.

It is an arithmetic number, because the mean of its divisors is an integer number (66496366482).

Almost surely, 2^639388138875 is an apocalyptic number.

639388138875 is a deficient number, since it is larger than the sum of its proper divisors (424553724837).

639388138875 is a wasteful number, since it uses less digits than its factorization.

639388138875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1705035055 (or 1705035045 counting only the distinct ones).

The product of its digits is 209018880, while the sum is 69.

The spelling of 639388138875 in words is "six hundred thirty-nine billion, three hundred eighty-eight million, one hundred thirty-eight thousand, eight hundred seventy-five".