639117852 has 12 divisors (see below), whose sum is σ = 1491275016. Its totient is φ = 213039280.

The previous prime is 639117833. The next prime is 639117887. The reversal of 639117852 is 258711936.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26629899 + ... + 26629922.

It is an arithmetic number, because the mean of its divisors is an integer number (124272918).

Almost surely, 2^639117852 is an apocalyptic number.

It is an amenable number.

639117852 is an abundant number, since it is smaller than the sum of its proper divisors (852157164).

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

639117852 is a wasteful number, since it uses less digits than its factorization.

639117852 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53259828 (or 53259826 counting only the distinct ones).

The product of its digits is 90720, while the sum is 42.

The square root of 639117852 is about 25280.7802885908. The cubic root of 639117852 is about 861.3777501534.

The spelling of 639117852 in words is "six hundred thirty-nine million, one hundred seventeen thousand, eight hundred fifty-two".