639392 has 48 divisors (see below), whose sum is σ = 1428840. Its totient is φ = 279552.

The previous prime is 639391. The next prime is 639433. The reversal of 639392 is 293936.

It can be written as a sum of positive squares in 4 ways, for example, as 512656 + 126736 = 716^2 + 356^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a d-powerful number, because it can be written as 6⁶ + 3³ + 3⁷ + 9⁵ + 9⁶ + 2⁵ .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 639392.

It is not an unprimeable number, because it can be changed into a prime (639391) 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 7 ways as a sum of consecutive naturals, for example, 12038 + ... + 12090.

2⁶³⁹³⁹² 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 639392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (714420).

639392 is an abundant number, since it is smaller than the sum of its proper divisors (789448).

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

639392 is a wasteful number, since it uses less digits than its factorization.

639392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105 (or 97 counting only the distinct ones).

The product of its digits is 8748, while the sum is 32.

The square root of 639392 is about 799.6199097071. The cubic root of 639392 is about 86.1500894490.

The spelling of 639392 in words is "six hundred thirty-nine thousand, three hundred ninety-two".