639072 has 72 divisors (see below), whose sum is σ = 2083536. Its totient is φ = 182016.

The previous prime is 639053. The next prime is 639083. The reversal of 639072 is 270936.

It is a tau number, because it is divible by the number of its divisors (72).

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 639072.

It is an unprimeable number.

639072 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1858 + ... + 2174.

It is an arithmetic number, because the mean of its divisors is an integer number (28938).

2⁶³⁹⁰⁷² 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 639072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1041768).

639072 is an abundant number, since it is smaller than the sum of its proper divisors (1444464).

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

639072 is a wasteful number, since it uses less digits than its factorization.

639072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340 (or 329 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 27.

The square root of 639072 is about 799.4197895974. The cubic root of 639072 is about 86.1357150490.

Subtracting from 639072 its product of nonzero digits (2268), we obtain a square (636804 = 798²).

It can be divided in two parts, 63 and 9072, that multiplied together give a square (571536 = 756²).

The spelling of 639072 in words is "six hundred thirty-nine thousand, seventy-two".