638885520 has 480 divisors, whose sum is σ = 2708160000. Its totient is φ = 134120448.

The previous prime is 638885503. The next prime is 638885531. The reversal of 638885520 is 25588836.

It is a happy number.

638885520 is a `hidden beast` number, since 638 + 8 + 8 + 5 + 5 + 2 + 0 = 666.

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, 3210381 + ... + 3210579.

It is an arithmetic number, because the mean of its divisors is an integer number (5642000).

Almost surely, 2^638885520 is an apocalyptic number.

638885520 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 638885520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1354080000).

638885520 is an abundant number, since it is smaller than the sum of its proper divisors (2069274480).

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

638885520 is a wasteful number, since it uses less digits than its factorization.

638885520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252 (or 229 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 45.

The square root of 638885520 is about 25276.1848386975. The cubic root of 638885520 is about 861.2733615447.

The spelling of 638885520 in words is "six hundred thirty-eight million, eight hundred eighty-five thousand, five hundred twenty".