638890560 has 672 divisors, whose sum is σ = 2845320192. Its totient is φ = 127733760.

The previous prime is 638890541. The next prime is 638890621. The reversal of 638890560 is 65098836.

638890560 is a `hidden beast` number, since 6 + 3 + 8 + 89 + 0 + 560 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a super-2 number, since 2×638890560² = 816362295314227200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 9535647 + ... + 9535713.

Almost surely, 2^638890560 is an apocalyptic number.

638890560 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638890560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1422660096).

638890560 is an abundant number, since it is smaller than the sum of its proper divisors (2206429632).

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

638890560 is a wasteful number, since it uses less digits than its factorization.

638890560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151 (or 138 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 638890560 is about 25276.2845370913. The cubic root of 638890560 is about 861.2756263251.

It can be divided in two parts, 638 and 890560, that added together give a palindrome (891198).

The spelling of 638890560 in words is "six hundred thirty-eight million, eight hundred ninety thousand, five hundred sixty".