640589904 has 160 divisors (see below), whose sum is σ = 1918627200. Its totient is φ = 204456960.

The previous prime is 640589899. The next prime is 640589909. The reversal of 640589904 is 409985046.

It is a happy number.

640589904 is a `hidden beast` number, since 64 + 0 + 589 + 9 + 0 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (640589899) and next prime (640589909).

It is a self number, because there is not a number n which added to its sum of digits gives 640589904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640589909) 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 31 ways as a sum of consecutive naturals, for example, 1044702 + ... + 1045314.

It is an arithmetic number, because the mean of its divisors is an integer number (11991420).

Almost surely, 2^640589904 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 640589904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (959313600).

640589904 is an abundant number, since it is smaller than the sum of its proper divisors (1278037296).

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

640589904 is a wasteful number, since it uses less digits than its factorization.

640589904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 730 (or 718 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 640589904 is about 25309.8775974915. The cubic root of 640589904 is about 862.0385675471.

The spelling of 640589904 in words is "six hundred forty million, five hundred eighty-nine thousand, nine hundred four".