638900 has 18 divisors (see below), whose sum is σ = 1386630. Its totient is φ = 255520.

The previous prime is 638893. The next prime is 638923. The reversal of 638900 is 9836.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 8464 + 630436 = 92^2 + 794^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 638900.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 638900.

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 5 ways as a sum of consecutive naturals, for example, 3095 + ... + 3294.

It is an arithmetic number, because the mean of its divisors is an integer number (77035).

2⁶³⁸⁹⁰⁰ is an apocalyptic number.

It is an amenable number.

638900 is an abundant number, since it is smaller than the sum of its proper divisors (747730).

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

638900 is a wasteful number, since it uses less digits than its factorization.

638900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6403 (or 6396 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 638900 is about 799.3122043357. The cubic root of 638900 is about 86.1279868263.

The spelling of 638900 in words is "six hundred thirty-eight thousand, nine hundred".