638815732 has 12 divisors (see below), whose sum is σ = 1183688100. Its totient is φ = 300619136.

The previous prime is 638815699. The next prime is 638815733. The reversal of 638815732 is 237518836.

638815732 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 291589776 + 347225956 = 17076^2 + 18634^2 .

It is a super-3 number, since 3×638815732³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638815733) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4697107 + ... + 4697242.

It is an arithmetic number, because the mean of its divisors is an integer number (98640675).

Almost surely, 2^638815732 is an apocalyptic number.

It is an amenable number.

638815732 is a deficient number, since it is larger than the sum of its proper divisors (544872368).

638815732 is a wasteful number, since it uses less digits than its factorization.

638815732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9394370 (or 9394368 counting only the distinct ones).

The product of its digits is 241920, while the sum is 43.

The square root of 638815732 is about 25274.8042920217. The cubic root of 638815732 is about 861.2420003007.

The spelling of 638815732 in words is "six hundred thirty-eight million, eight hundred fifteen thousand, seven hundred thirty-two".