636904 has 8 divisors (see below), whose sum is σ = 1194210. Its totient is φ = 318448.

The previous prime is 636877. The next prime is 636917. The reversal of 636904 is 409636.

It can be written as a sum of positive squares in only one way, i.e., 636804 + 100 = 798^2 + 10^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39799 + ... + 39814.

2⁶³⁶⁹⁰⁴ is an apocalyptic number.

It is an amenable number.

636904 is a deficient number, since it is larger than the sum of its proper divisors (557306).

636904 is a wasteful number, since it uses less digits than its factorization.

636904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79619 (or 79615 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 636904 is about 798.0626541820. The cubic root of 636904 is about 86.0382018849.

It can be divided in two parts, 636 and 904, that added together give a triangular number (1540 = T₅₅).

The spelling of 636904 in words is "six hundred thirty-six thousand, nine hundred four".