638138763950 has 48 divisors (see below), whose sum is σ = 1311399681120. Its totient is φ = 229795230720.

The previous prime is 638138763937. The next prime is 638138763991. The reversal of 638138763950 is 59367831836.

It is a happy number.

It is a Smith number, since the sum of its digits (59) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 638138763950.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16301135 + ... + 16340234.

It is an arithmetic number, because the mean of its divisors is an integer number (27320826690).

Almost surely, 2^638138763950 is an apocalyptic number.

638138763950 is an abundant number, since it is smaller than the sum of its proper divisors (673260917170).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638138763950 is a wasteful number, since it uses less digits than its factorization.

638138763950 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32641421 (or 32641416 counting only the distinct ones).

The product of its (nonzero) digits is 19595520, while the sum is 59.

The spelling of 638138763950 in words is "six hundred thirty-eight billion, one hundred thirty-eight million, seven hundred sixty-three thousand, nine hundred fifty".