638790 has 32 divisors (see below), whose sum is σ = 1555200. Its totient is φ = 167904.

The previous prime is 638767. The next prime is 638801. The reversal of 638790 is 97836.

It is a happy number.

It is a nialpdrome in base 15.

It is a congruent number.

It is an unprimeable number.

638790 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 15 ways as a sum of consecutive naturals, for example, 3111 + ... + 3309.

It is an arithmetic number, because the mean of its divisors is an integer number (48600).

2⁶³⁸⁷⁹⁰ is an apocalyptic number.

638790 is an abundant number, since it is smaller than the sum of its proper divisors (916410).

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

638790 is a wasteful number, since it uses less digits than its factorization.

638790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316.

The product of its (nonzero) digits is 9072, while the sum is 33.

The square root of 638790 is about 799.2433922154. The cubic root of 638790 is about 86.1230436310.

The spelling of 638790 in words is "six hundred thirty-eight thousand, seven hundred ninety".