640432968 has 64 divisors (see below), whose sum is σ = 1888849920. Its totient is φ = 177076800.

The previous prime is 640432957. The next prime is 640432979. The reversal of 640432968 is 869234046.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (640432957) and next prime (640432979).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56278 + ... + 66693.

It is an arithmetic number, because the mean of its divisors is an integer number (29513280).

Almost surely, 2^640432968 is an apocalyptic number.

It is an amenable number.

640432968 is an abundant number, since it is smaller than the sum of its proper divisors (1248416952).

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

640432968 is a wasteful number, since it uses less digits than its factorization.

640432968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123018 (or 123014 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 42.

The square root of 640432968 is about 25306.7771160217. Note that the first 3 decimals coincide. The cubic root of 640432968 is about 861.9681658059.

The spelling of 640432968 in words is "six hundred forty million, four hundred thirty-two thousand, nine hundred sixty-eight".