639541904 has 80 divisors (see below), whose sum is σ = 1374197760. Its totient is φ = 286986240.

The previous prime is 639541897. The next prime is 639541909. The reversal of 639541904 is 409145936.

It is not an unprimeable number, because it can be changed into a prime (639541909) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 615017 + ... + 616055.

It is an arithmetic number, because the mean of its divisors is an integer number (17177472).

Almost surely, 2^639541904 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 639541904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (687098880).

639541904 is an abundant number, since it is smaller than the sum of its proper divisors (734655856).

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

639541904 is a wasteful number, since it uses less digits than its factorization.

639541904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1168 (or 1162 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 41.

The square root of 639541904 is about 25289.1657434562. The cubic root of 639541904 is about 861.5682148705.

The spelling of 639541904 in words is "six hundred thirty-nine million, five hundred forty-one thousand, nine hundred four".