639912 has 64 divisors (see below), whose sum is σ = 1975680. Its totient is φ = 168192.

The previous prime is 639911. The next prime is 639937. The reversal of 639912 is 219936.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 639912.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 639912.

It is not an unprimeable number, because it can be changed into a prime (639911) 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, 2038 + ... + 2330.

It is an arithmetic number, because the mean of its divisors is an integer number (30870).

2⁶³⁹⁹¹² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (987840).

639912 is an abundant number, since it is smaller than the sum of its proper divisors (1335768).

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

639912 is a wasteful number, since it uses less digits than its factorization.

639912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322 (or 318 counting only the distinct ones).

The product of its digits is 2916, while the sum is 30.

The square root of 639912 is about 799.9449981092. The cubic root of 639912 is about 86.1734376233.

It can be divided in two parts, 639 and 912, that added together give a palindrome (1551).

The spelling of 639912 in words is "six hundred thirty-nine thousand, nine hundred twelve".