639144 has 64 divisors (see below), whose sum is σ = 1944000. Its totient is φ = 192960.

The previous prime is 639143. The next prime is 639151. The reversal of 639144 is 441936.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

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 639144.

It is not an unprimeable number, because it can be changed into a prime (639143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2242 + ... + 2510.

It is an arithmetic number, because the mean of its divisors is an integer number (30375).

2⁶³⁹¹⁴⁴ 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 639144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (972000).

639144 is an abundant number, since it is smaller than the sum of its proper divisors (1304856).

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

639144 is a wasteful number, since it uses less digits than its factorization.

639144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295 (or 285 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 639144 is about 799.4648209896. The cubic root of 639144 is about 86.1389497073.

The spelling of 639144 in words is "six hundred thirty-nine thousand, one hundred forty-four".