638500 has 24 divisors (see below), whose sum is σ = 1395576. Its totient is φ = 255200.

The previous prime is 638489. The next prime is 638501. The reversal of 638500 is 5836.

638500 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 11236 + 627264 = 106^2 + 792^2 .

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (638501) by changing a digit.

638500 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 139 + ... + 1138.

It is an arithmetic number, because the mean of its divisors is an integer number (58149).

2⁶³⁸⁵⁰⁰ is an apocalyptic number.

It is an amenable number.

638500 is an abundant number, since it is smaller than the sum of its proper divisors (757076).

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

638500 is a wasteful number, since it uses less digits than its factorization.

638500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1296 (or 1284 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 638500 is about 799.0619500389. The cubic root of 638500 is about 86.1100088501.

The spelling of 638500 in words is "six hundred thirty-eight thousand, five hundred".