638643170 has 16 divisors (see below), whose sum is σ = 1254063168. Its totient is φ = 232233840.

The previous prime is 638643151. The next prime is 638643193. The reversal of 638643170 is 71346836.

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, 2902814 + ... + 2903033.

It is an arithmetic number, because the mean of its divisors is an integer number (78378948).

Almost surely, 2^638643170 is an apocalyptic number.

638643170 is a deficient number, since it is larger than the sum of its proper divisors (615419998).

638643170 is a wasteful number, since it uses less digits than its factorization.

638643170 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5805865.

The product of its (nonzero) digits is 72576, while the sum is 38.

The square root of 638643170 is about 25271.3903456062. The cubic root of 638643170 is about 861.1644447978.

The spelling of 638643170 in words is "six hundred thirty-eight million, six hundred forty-three thousand, one hundred seventy".