638800 has 30 divisors (see below), whose sum is σ = 1535678. Its totient is φ = 255360.

The previous prime is 638767. The next prime is 638801. The reversal of 638800 is 8836.

It can be written as a sum of positive squares in 3 ways, for example, as 5184 + 633616 = 72^2 + 796^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638801) 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 5 ways as a sum of consecutive naturals, for example, 399 + ... + 1198.

2⁶³⁸⁸⁰⁰ is an apocalyptic number.

638800 is the 400-th decagonal number.

It is an amenable number.

638800 is an abundant number, since it is smaller than the sum of its proper divisors (896878).

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

638800 is a wasteful number, since it uses less digits than its factorization.

638800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1615 (or 1604 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 638800 is about 799.2496481075. The cubic root of 638800 is about 86.1234930359.

638800 divided by its sum of digits (25) gives a palindrome (25552).

The spelling of 638800 in words is "six hundred thirty-eight thousand, eight hundred".