638799 has 16 divisors (see below), whose sum is σ = 1025280. Its totient is φ = 345600.

The previous prime is 638767. The next prime is 638801. The reversal of 638799 is 997836.

It is a happy number.

It is not a de Polignac number, because 638799 - 2⁵ = 638767 is a prime.

638799 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 638799.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638719) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 402 + ... + 1199.

It is an arithmetic number, because the mean of its divisors is an integer number (64080).

2⁶³⁸⁷⁹⁹ is an apocalyptic number.

638799 is a deficient number, since it is larger than the sum of its proper divisors (386481).

638799 is a wasteful number, since it uses less digits than its factorization.

638799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1630.

The product of its digits is 81648, while the sum is 42.

The square root of 638799 is about 799.2490225205. The cubic root of 638799 is about 86.1234480956.

The spelling of 638799 in words is "six hundred thirty-eight thousand, seven hundred ninety-nine".