638317968 has 40 divisors (see below), whose sum is σ = 1667527200. Its totient is φ = 210380544.

The previous prime is 638317963. The next prime is 638317997. The reversal of 638317968 is 869713836.

It is a self number, because there is not a number n which added to its sum of digits gives 638317968.

It is not an unprimeable number, because it can be changed into a prime (638317961) 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, 70438 + ... + 78981.

It is an arithmetic number, because the mean of its divisors is an integer number (41688180).

Almost surely, 2^638317968 is an apocalyptic number.

It is an amenable number.

638317968 is an abundant number, since it is smaller than the sum of its proper divisors (1029209232).

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

638317968 is a wasteful number, since it uses less digits than its factorization.

638317968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149519 (or 149513 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 51.

The square root of 638317968 is about 25264.9553334258. The cubic root of 638317968 is about 861.0182494672.

The spelling of 638317968 in words is "six hundred thirty-eight million, three hundred seventeen thousand, nine hundred sixty-eight".