638240 has 24 divisors (see below), whose sum is σ = 1508220. Its totient is φ = 255232.

The previous prime is 638233. The next prime is 638263. The reversal of 638240 is 42836.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 633616 + 4624 = 796^2 + 68^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1835 + ... + 2154.

2⁶³⁸²⁴⁰ is an apocalyptic number.

It is an amenable number.

638240 is an abundant number, since it is smaller than the sum of its proper divisors (869980).

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

638240 is a wasteful number, since it uses less digits than its factorization.

638240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4004 (or 3996 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 638240 is about 798.8992427084. The cubic root of 638240 is about 86.0983191389.

It can be divided in two parts, 638 and 240, that added together give a palindrome (878).

The spelling of 638240 in words is "six hundred thirty-eight thousand, two hundred forty".