639138357 has 56 divisors (see below), whose sum is σ = 1125982368. Its totient is φ = 357501600.

The previous prime is 639138349. The next prime is 639138371. The reversal of 639138357 is 753831936.

639138357 is a `hidden beast` number, since 639 + 1 + 3 + 8 + 3 + 5 + 7 = 666.

It is not a de Polignac number, because 639138357 - 2³ = 639138349 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639138347) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 101182 + ... + 107312.

It is an arithmetic number, because the mean of its divisors is an integer number (20106828).

Almost surely, 2^639138357 is an apocalyptic number.

It is an amenable number.

639138357 is a deficient number, since it is larger than the sum of its proper divisors (486844011).

639138357 is a wasteful number, since it uses less digits than its factorization.

639138357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6173 (or 6158 counting only the distinct ones).

The product of its digits is 408240, while the sum is 45.

The square root of 639138357 is about 25281.1858305737. The cubic root of 639138357 is about 861.3869619974.

The spelling of 639138357 in words is "six hundred thirty-nine million, one hundred thirty-eight thousand, three hundred fifty-seven".