640436500 has 48 divisors (see below), whose sum is σ = 1525882176. Its totient is φ = 232884000.

The previous prime is 640436497. The next prime is 640436501. The reversal of 640436500 is 5634046.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640436501) 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 15 ways as a sum of consecutive naturals, for example, 52722 + ... + 63721.

It is an arithmetic number, because the mean of its divisors is an integer number (31789212).

Almost surely, 2^640436500 is an apocalyptic number.

It is an amenable number.

640436500 is an abundant number, since it is smaller than the sum of its proper divisors (885445676).

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

640436500 is a wasteful number, since it uses less digits than its factorization.

640436500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116473 (or 116461 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 28.

The square root of 640436500 is about 25306.8468996041. The cubic root of 640436500 is about 861.9697503933.

The spelling of 640436500 in words is "six hundred forty million, four hundred thirty-six thousand, five hundred".