639704 has 16 divisors (see below), whose sum is σ = 1291920. Its totient is φ = 295200.

The previous prime is 639703. The next prime is 639713. The reversal of 639704 is 407936.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2972 + ... + 3179.

It is an arithmetic number, because the mean of its divisors is an integer number (80745).

2⁶³⁹⁷⁰⁴ is an apocalyptic number.

It is an amenable number.

639704 is an abundant number, since it is smaller than the sum of its proper divisors (652216).

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

639704 is a wasteful number, since it uses less digits than its factorization.

639704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6170 (or 6166 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 639704 is about 799.8149786044. The cubic root of 639704 is about 86.1640998720.

The spelling of 639704 in words is "six hundred thirty-nine thousand, seven hundred four".