639447318 has 64 divisors (see below), whose sum is σ = 1499731200. Its totient is φ = 201398400.

The previous prime is 639447317. The next prime is 639447329. The reversal of 639447318 is 813744936.

639447318 is a `hidden beast` number, since 639 + 4 + 4 + 7 + 3 + 1 + 8 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639447313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 607893 + ... + 608943.

It is an arithmetic number, because the mean of its divisors is an integer number (23433300).

Almost surely, 2^639447318 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639447318, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (749865600).

639447318 is an abundant number, since it is smaller than the sum of its proper divisors (860283882).

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

639447318 is a wasteful number, since it uses less digits than its factorization.

639447318 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1674 (or 1668 counting only the distinct ones).

The product of its digits is 435456, while the sum is 45.

The square root of 639447318 is about 25287.2955849375. The cubic root of 639447318 is about 861.5257384727.

The spelling of 639447318 in words is "six hundred thirty-nine million, four hundred forty-seven thousand, three hundred eighteen".