639504 has 30 divisors (see below), whose sum is σ = 1790126. Its totient is φ = 213120.

The previous prime is 639493. The next prime is 639511. The reversal of 639504 is 405936.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 518400 + 121104 = 720^2 + 348^2 .

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2077 + ... + 2364.

2⁶³⁹⁵⁰⁴ is an apocalyptic number.

It is an amenable number.

639504 is an abundant number, since it is smaller than the sum of its proper divisors (1150622).

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

639504 is a wasteful number, since it uses less digits than its factorization.

639504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4455 (or 4446 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 639504 is about 799.6899399142. The cubic root of 639504 is about 86.1551193559.

The spelling of 639504 in words is "six hundred thirty-nine thousand, five hundred four".