639232256 has 72 divisors (see below), whose sum is σ = 1381551864. Its totient is φ = 293437440.

The previous prime is 639232247. The next prime is 639232291. The reversal of 639232256 is 652232936.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 64000000 + 575232256 = 8000^2 + 23984^2 .

It is a super-2 number, since 2×639232256² = 817235754221699072, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 801650 + ... + 802446.

Almost surely, 2^639232256 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 639232256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (690775932).

639232256 is an abundant number, since it is smaller than the sum of its proper divisors (742319608).

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

639232256 is a wasteful number, since it uses less digits than its factorization.

639232256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1067 (or 1053 counting only the distinct ones).

The product of its digits is 116640, while the sum is 38.

The square root of 639232256 is about 25283.0428548464. The cubic root of 639232256 is about 861.4291434817.

The spelling of 639232256 in words is "six hundred thirty-nine million, two hundred thirty-two thousand, two hundred fifty-six".