638185968 has 120 divisors (see below), whose sum is σ = 2130006528. Its totient is φ = 174404736.

The previous prime is 638185963. The next prime is 638185969. The reversal of 638185968 is 869581836.

638185968 is a `hidden beast` number, since 6 + 38 + 18 + 596 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638185963) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9421 + ... + 36947.

Almost surely, 2^638185968 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638185968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1065003264).

638185968 is an abundant number, since it is smaller than the sum of its proper divisors (1491820560).

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

638185968 is a wasteful number, since it uses less digits than its factorization.

638185968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27571 (or 27562 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 54.

The square root of 638185968 is about 25262.3428842220. The cubic root of 638185968 is about 860.9588943861.

The spelling of 638185968 in words is "six hundred thirty-eight million, one hundred eighty-five thousand, nine hundred sixty-eight".