639633025 has 6 divisors (see below), whose sum is σ = 793144982. Its totient is φ = 511706400.

The previous prime is 639632993. The next prime is 639633031. The reversal of 639633025 is 520336936.

It can be written as a sum of positive squares in 3 ways, for example, as 24245776 + 615387249 = 4924^2 + 24807^2 .

It is not a de Polignac number, because 639633025 - 2⁵ = 639632993 is a prime.

It is a Duffinian 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, 12792636 + ... + 12792685.

Almost surely, 2^639633025 is an apocalyptic number.

It is an amenable number.

639633025 is a deficient number, since it is larger than the sum of its proper divisors (153511957).

639633025 is a wasteful number, since it uses less digits than its factorization.

639633025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25585331 (or 25585326 counting only the distinct ones).

The product of its (nonzero) digits is 87480, while the sum is 37.

The square root of 639633025 is about 25290.9672610598. The cubic root of 639633025 is about 861.6091312560.

The spelling of 639633025 in words is "six hundred thirty-nine million, six hundred thirty-three thousand, twenty-five".