639720976 has 40 divisors (see below), whose sum is σ = 1312058880. Its totient is φ = 301639296.

The previous prime is 639720883. The next prime is 639720979. The reversal of 639720976 is 679027936.

It is not an unprimeable number, because it can be changed into a prime (639720979) by changing a digit.

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, 3921 + ... + 35983.

It is an arithmetic number, because the mean of its divisors is an integer number (32801472).

Almost surely, 2^639720976 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 639720976, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (656029440).

639720976 is an abundant number, since it is smaller than the sum of its proper divisors (672337904).

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

639720976 is a wasteful number, since it uses less digits than its factorization.

639720976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32143 (or 32137 counting only the distinct ones).

The product of its (nonzero) digits is 857304, while the sum is 49.

The square root of 639720976 is about 25292.7059841370. The cubic root of 639720976 is about 861.6486205197.

The spelling of 639720976 in words is "six hundred thirty-nine million, seven hundred twenty thousand, nine hundred seventy-six".