639570644 has 24 divisors (see below), whose sum is σ = 1150372608. Its totient is φ = 310944960.

The previous prime is 639570619. The next prime is 639570671. The reversal of 639570644 is 446075936.

It is a junction number, because it is equal to n+sod(n) for n = 639570595 and 639570604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43997 + ... + 56699.

It is an arithmetic number, because the mean of its divisors is an integer number (47932192).

Almost surely, 2^639570644 is an apocalyptic number.

It is an amenable number.

639570644 is a deficient number, since it is larger than the sum of its proper divisors (510801964).

639570644 is a wasteful number, since it uses less digits than its factorization.

639570644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13055 (or 13053 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 44.

The square root of 639570644 is about 25289.7339645952. The cubic root of 639570644 is about 861.5811205141.

The spelling of 639570644 in words is "six hundred thirty-nine million, five hundred seventy thousand, six hundred forty-four".