639660704 has 24 divisors (see below), whose sum is σ = 1267363188. Its totient is φ = 317790720.

The previous prime is 639660691. The next prime is 639660731. The reversal of 639660704 is 407066936.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 618019600 + 21641104 = 24860^2 + 4652^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58637 + ... + 68684.

Almost surely, 2^639660704 is an apocalyptic number.

It is an amenable number.

639660704 is a deficient number, since it is larger than the sum of its proper divisors (627702484).

639660704 is a wasteful number, since it uses less digits than its factorization.

639660704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127488 (or 127480 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 41.

The square root of 639660704 is about 25291.5144663185. The cubic root of 639660704 is about 861.6215592859.

The spelling of 639660704 in words is "six hundred thirty-nine million, six hundred sixty thousand, seven hundred four".