638317971 has 24 divisors (see below), whose sum is σ = 949502736. Its totient is φ = 412968960.

The previous prime is 638317963. The next prime is 638317997. The reversal of 638317971 is 179713836.

638317971 is a `hidden beast` number, since 638 + 3 + 1 + 7 + 9 + 7 + 1 = 666.

It is not a de Polignac number, because 638317971 - 2³ = 638317963 is a prime.

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 23 ways as a sum of consecutive naturals, for example, 66736 + ... + 75698.

It is an arithmetic number, because the mean of its divisors is an integer number (39562614).

Almost surely, 2^638317971 is an apocalyptic number.

638317971 is a deficient number, since it is larger than the sum of its proper divisors (311184765).

638317971 is a wasteful number, since it uses less digits than its factorization.

638317971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9203 (or 9200 counting only the distinct ones).

The product of its digits is 190512, while the sum is 45.

The square root of 638317971 is about 25264.9553927966. The cubic root of 638317971 is about 861.0182508161.

The spelling of 638317971 in words is "six hundred thirty-eight million, three hundred seventeen thousand, nine hundred seventy-one".