638974031 has 4 divisors (see below), whose sum is σ = 642217752. Its totient is φ = 635730312.

The previous prime is 638974027. The next prime is 638974033. The reversal of 638974031 is 130479836.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 638974031 - 2² = 638974027 is a prime.

It is a super-2 number, since 2×638974031² = 816575624584777922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638974031.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638974033) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1621565 + ... + 1621958.

It is an arithmetic number, because the mean of its divisors is an integer number (160554438).

Almost surely, 2^638974031 is an apocalyptic number.

638974031 is a deficient number, since it is larger than the sum of its proper divisors (3243721).

638974031 is a wasteful number, since it uses less digits than its factorization.

638974031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3243720.

The product of its (nonzero) digits is 108864, while the sum is 41.

The square root of 638974031 is about 25277.9356554288. The cubic root of 638974031 is about 861.3131332220.

The spelling of 638974031 in words is "six hundred thirty-eight million, nine hundred seventy-four thousand, thirty-one".