639822 has 8 divisors (see below), whose sum is σ = 1279656. Its totient is φ = 213272.

The previous prime is 639757. The next prime is 639833. The reversal of 639822 is 228936.

639822 is nontrivially palindromic in base 15.

639822 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

639822 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 639822.

It is a congruent number.

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, 53313 + ... + 53324.

It is an arithmetic number, because the mean of its divisors is an integer number (159957).

2⁶³⁹⁸²² is an apocalyptic number.

639822 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

639822 is a wasteful number, since it uses less digits than its factorization.

639822 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106642.

The product of its digits is 5184, while the sum is 30.

The square root of 639822 is about 799.8887422636. Note that the first 3 decimals coincide. The cubic root of 639822 is about 86.1693974985.

The spelling of 639822 in words is "six hundred thirty-nine thousand, eight hundred twenty-two".