639021312 has 90 divisors (see below), whose sum is σ = 1905507758. Its totient is φ = 213000192.

The previous prime is 639021301. The next prime is 639021343. The reversal of 639021312 is 213120936.

639021312 is a `hidden beast` number, since 639 + 0 + 2 + 13 + 12 = 666.

It can be written as a sum of positive squares in only one way, i.e., 383533056 + 255488256 = 19584^2 + 15984^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 5328 + ... + 36144.

Almost surely, 2^639021312 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 639021312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (952753879).

639021312 is an abundant number, since it is smaller than the sum of its proper divisors (1266486446).

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

639021312 is an equidigital number, since it uses as much as digits as its factorization.

639021312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30845 (or 30822 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 639021312 is about 25278.8708608593. The cubic root of 639021312 is about 861.3343770389.

The spelling of 639021312 in words is "six hundred thirty-nine million, twenty-one thousand, three hundred twelve".