638899056 has 40 divisors (see below), whose sum is σ = 1833878160. Its totient is φ = 212966208.

The previous prime is 638899021. The next prime is 638899103. The reversal of 638899056 is 650998836.

It is a super-2 number, since 2×638899056² = 816384007515382272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 638898993 and 638899011.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 739035 + ... + 739898.

It is an arithmetic number, because the mean of its divisors is an integer number (45846954).

Almost surely, 2^638899056 is an apocalyptic number.

It is an amenable number.

638899056 is an abundant number, since it is smaller than the sum of its proper divisors (1194979104).

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

638899056 is a wasteful number, since it uses less digits than its factorization.

638899056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1478950 (or 1478938 counting only the distinct ones).

The product of its (nonzero) digits is 2799360, while the sum is 54.

The square root of 638899056 is about 25276.4525992078. The cubic root of 638899056 is about 861.2794440709.

The spelling of 638899056 in words is "six hundred thirty-eight million, eight hundred ninety-nine thousand, fifty-six".