639202464 has 72 divisors (see below), whose sum is σ = 1862101332. Its totient is φ = 207866880.

The previous prime is 639202463. The next prime is 639202471. The reversal of 639202464 is 464202936.

It can be written as a sum of positive squares in 2 ways, for example, as 399200400 + 240002064 = 19980^2 + 15492^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (639202463) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15259 + ... + 38874.

Almost surely, 2^639202464 is an apocalyptic number.

It is an amenable number.

639202464 is an abundant number, since it is smaller than the sum of its proper divisors (1222898868).

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

639202464 is a wasteful number, since it uses less digits than its factorization.

639202464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54190 (or 54179 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The square root of 639202464 is about 25282.4536783913. The cubic root of 639202464 is about 861.4157607112.

The spelling of 639202464 in words is "six hundred thirty-nine million, two hundred two thousand, four hundred sixty-four".