638839973 has 12 divisors (see below), whose sum is σ = 669605580. Its totient is φ = 609434496.

The previous prime is 638839937. The next prime is 638839979. The reversal of 638839973 is 379938836.

638839973 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 220760164 + 418079809 = 14858^2 + 20447^2 .

It is not a de Polignac number, because 638839973 - 2²⁴ = 622062757 is a prime.

It is a super-2 number, since 2×638839973² = 816233022205281458, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638839979) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 227663 + ... + 230451.

It is an arithmetic number, because the mean of its divisors is an integer number (55800465).

Almost surely, 2^638839973 is an apocalyptic number.

It is an amenable number.

638839973 is a deficient number, since it is larger than the sum of its proper divisors (30765607).

638839973 is a wasteful number, since it uses less digits than its factorization.

638839973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3268 (or 3245 counting only the distinct ones).

The product of its digits is 5878656, while the sum is 56.

The square root of 638839973 is about 25275.2838361906. The cubic root of 638839973 is about 861.2528939497.

The spelling of 638839973 in words is "six hundred thirty-eight million, eight hundred thirty-nine thousand, nine hundred seventy-three".