639044 has 24 divisors (see below), whose sum is σ = 1323840. Its totient is φ = 264096.

The previous prime is 639043. The next prime is 639049. The reversal of 639044 is 440936.

It is not an unprimeable number, because it can be changed into a prime (639043) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 419 + ... + 1205.

It is an arithmetic number, because the mean of its divisors is an integer number (55160).

2⁶³⁹⁰⁴⁴ 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 639044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (661920).

639044 is an abundant number, since it is smaller than the sum of its proper divisors (684796).

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

639044 is a wasteful number, since it uses less digits than its factorization.

639044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 827 (or 825 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 639044 is about 799.4022767043. The cubic root of 639044 is about 86.1344570608.

The spelling of 639044 in words is "six hundred thirty-nine thousand, forty-four".