638842 has 16 divisors (see below), whose sum is σ = 1005480. Its totient is φ = 304128.

The previous prime is 638839. The next prime is 638857. The reversal of 638842 is 248836.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 561001 + 77841 = 749^2 + 279^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6538 + ... + 6634.

2⁶³⁸⁸⁴² is an apocalyptic number.

638842 is a deficient number, since it is larger than the sum of its proper divisors (366638).

638842 is a wasteful number, since it uses less digits than its factorization.

638842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225.

The product of its digits is 9216, while the sum is 31.

The square root of 638842 is about 799.2759223197. The cubic root of 638842 is about 86.1253804850.

The spelling of 638842 in words is "six hundred thirty-eight thousand, eight hundred forty-two".