638043975 has 18 divisors (see below), whose sum is σ = 1142808056. Its totient is φ = 340290000.

The previous prime is 638043961. The next prime is 638043977. The reversal of 638043975 is 579340836.

638043975 is a `hidden beast` number, since 638 + 0 + 4 + 3 + 9 + 7 + 5 = 666.

638043975 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 638043975 - 2⁸ = 638043719 is a prime.

It is a super-2 number, since 2×638043975² = 814200228067601250, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 638043975.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638043977) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1417651 + ... + 1418100.

Almost surely, 2^638043975 is an apocalyptic number.

638043975 is a deficient number, since it is larger than the sum of its proper divisors (504764081).

638043975 is a wasteful number, since it uses less digits than its factorization.

638043975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2835767 (or 2835759 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 45.

The square root of 638043975 is about 25259.5323590917. The cubic root of 638043975 is about 860.8950367176.

The spelling of 638043975 in words is "six hundred thirty-eight million, forty-three thousand, nine hundred seventy-five".