639388972 has 24 divisors (see below), whose sum is σ = 1187630640. Its totient is φ = 300157440.

The previous prime is 639388957. The next prime is 639389011. The reversal of 639388972 is 279883936.

It is a happy number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 17272 + ... + 39712.

It is an arithmetic number, because the mean of its divisors is an integer number (49484610).

Almost surely, 2^639388972 is an apocalyptic number.

It is an amenable number.

639388972 is a deficient number, since it is larger than the sum of its proper divisors (548241668).

639388972 is a wasteful number, since it uses less digits than its factorization.

639388972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22881 (or 22879 counting only the distinct ones).

The product of its digits is 3919104, while the sum is 55.

The square root of 639388972 is about 25286.1418963036. The cubic root of 639388972 is about 861.4995345368.

The spelling of 639388972 in words is "six hundred thirty-nine million, three hundred eighty-eight thousand, nine hundred seventy-two".