639640224 has 36 divisors (see below), whose sum is σ = 1818977706. Its totient is φ = 213213312.

The previous prime is 639640217. The next prime is 639640271. The reversal of 639640224 is 422046936.

639640224 is a `hidden beast` number, since 6 + 3 + 9 + 640 + 2 + 2 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 386830224 + 252810000 = 19668^2 + 15900^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 1110199 + ... + 1110774.

Almost surely, 2^639640224 is an apocalyptic number.

It is an amenable number.

639640224 is an abundant number, since it is smaller than the sum of its proper divisors (1179337482).

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

639640224 is a wasteful number, since it uses less digits than its factorization.

639640224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2220989 (or 2220978 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The square root of 639640224 is about 25291.1095841997. The cubic root of 639640224 is about 861.6123636828.

The spelling of 639640224 in words is "six hundred thirty-nine million, six hundred forty thousand, two hundred twenty-four".