638864401 has 12 divisors (see below), whose sum is σ = 750389952. Its totient is φ = 542277288.

The previous prime is 638864381. The next prime is 638864441. The reversal of 638864401 is 104468836.

It is not a de Polignac number, because 638864401 - 2⁷ = 638864273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638864441) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 58245 + ... + 68338.

It is an arithmetic number, because the mean of its divisors is an integer number (62532496).

Almost surely, 2^638864401 is an apocalyptic number.

It is an amenable number.

638864401 is a deficient number, since it is larger than the sum of its proper divisors (111525551).

638864401 is a wasteful number, since it uses less digits than its factorization.

638864401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126700 (or 126693 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 40.

The square root of 638864401 is about 25275.7670704570. The cubic root of 638864401 is about 861.2638713559.

The spelling of 638864401 in words is "six hundred thirty-eight million, eight hundred sixty-four thousand, four hundred one".