638491392 has 432 divisors, whose sum is σ = 2372348160. Its totient is φ = 160358400.

The previous prime is 638491369. The next prime is 638491393. The reversal of 638491392 is 293194836.

It is a happy number.

638491392 is a `hidden beast` number, since 638 + 4 + 9 + 1 + 3 + 9 + 2 = 666.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638491393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 10467042 + ... + 10467102.

Almost surely, 2^638491392 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 638491392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1186174080).

638491392 is an abundant number, since it is smaller than the sum of its proper divisors (1733856768).

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

638491392 is a wasteful number, since it uses less digits than its factorization.

638491392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160 (or 143 counting only the distinct ones).

The product of its digits is 279936, while the sum is 45.

The square root of 638491392 is about 25268.3872061515. The cubic root of 638491392 is about 861.0962188155.

The spelling of 638491392 in words is "six hundred thirty-eight million, four hundred ninety-one thousand, three hundred ninety-two".