638017938 has 32 divisors (see below), whose sum is σ = 1419076800. Its totient is φ = 212483808.

The previous prime is 638017937. The next prime is 638017979. The reversal of 638017938 is 839710836.

It is a happy number.

638017938 is a `hidden beast` number, since 638 + 0 + 1 + 7 + 9 + 3 + 8 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 638017893 and 638017902.

It is not an unprimeable number, because it can be changed into a prime (638017937) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64678 + ... + 73886.

It is an arithmetic number, because the mean of its divisors is an integer number (44346150).

Almost surely, 2^638017938 is an apocalyptic number.

638017938 is an abundant number, since it is smaller than the sum of its proper divisors (781058862).

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

638017938 is a wasteful number, since it uses less digits than its factorization.

638017938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10503 (or 10497 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The square root of 638017938 is about 25259.0169642447. The cubic root of 638017938 is about 860.8833262243.

The spelling of 638017938 in words is "six hundred thirty-eight million, seventeen thousand, nine hundred thirty-eight".