638857238 has 16 divisors (see below), whose sum is σ = 994680960. Its totient is φ = 307411200.

The previous prime is 638857231. The next prime is 638857243. The reversal of 638857238 is 832758836.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638857231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17243 + ... + 39686.

It is an arithmetic number, because the mean of its divisors is an integer number (62167560).

Almost surely, 2^638857238 is an apocalyptic number.

638857238 is a deficient number, since it is larger than the sum of its proper divisors (355823722).

638857238 is a wasteful number, since it uses less digits than its factorization.

638857238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57143.

The product of its digits is 1935360, while the sum is 50.

The square root of 638857238 is about 25275.6253730744. The cubic root of 638857238 is about 861.2606524902.

The spelling of 638857238 in words is "six hundred thirty-eight million, eight hundred fifty-seven thousand, two hundred thirty-eight".