640004000 has 48 divisors (see below), whose sum is σ = 1572499656. Its totient is φ = 256000000.

The previous prime is 640003943. The next prime is 640004017. The reversal of 640004000 is 400046.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 431143696 + 208860304 = 20764^2 + 14452^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76001 + ... + 84000.

Almost surely, 2^640004000 is an apocalyptic number.

It is an amenable number.

640004000 is an abundant number, since it is smaller than the sum of its proper divisors (932495656).

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

640004000 is a wasteful number, since it uses less digits than its factorization.

640004000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160026 (or 160008 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 640004000 is about 25298.3003381650. The cubic root of 640004000 is about 861.7756713713.

Adding to 640004000 its reverse (400046), we get a palindrome (640404046).

It can be divided in two parts, 64000 and 4000, that multiplied together give a square (256000000 = 16000²).

The spelling of 640004000 in words is "six hundred forty million, four thousand".