638183972 has 6 divisors (see below), whose sum is σ = 1116821958. Its totient is φ = 319091984.

The previous prime is 638183969. The next prime is 638183981. The reversal of 638183972 is 279381836.

It can be written as a sum of positive squares in only one way, i.e., 415099876 + 223084096 = 20374^2 + 14936^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79772993 + ... + 79773000.

It is an arithmetic number, because the mean of its divisors is an integer number (186136993).

Almost surely, 2^638183972 is an apocalyptic number.

It is an amenable number.

638183972 is a deficient number, since it is larger than the sum of its proper divisors (478637986).

638183972 is a wasteful number, since it uses less digits than its factorization.

638183972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159545997 (or 159545995 counting only the distinct ones).

The product of its digits is 435456, while the sum is 47.

The square root of 638183972 is about 25262.3033787499. The cubic root of 638183972 is about 860.9579968025.

The spelling of 638183972 in words is "six hundred thirty-eight million, one hundred eighty-three thousand, nine hundred seventy-two".