640626888 has 32 divisors (see below), whose sum is σ = 1747164960. Its totient is φ = 194129280.

The previous prime is 640626887. The next prime is 640626901. The reversal of 640626888 is 888626046.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (640626881) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 1213045 + ... + 1213572.

It is an arithmetic number, because the mean of its divisors is an integer number (54598905).

Almost surely, 2^640626888 is an apocalyptic number.

It is an amenable number.

640626888 is an abundant number, since it is smaller than the sum of its proper divisors (1106538072).

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

640626888 is a wasteful number, since it uses less digits than its factorization.

640626888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2426637 (or 2426633 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 48.

The square root of 640626888 is about 25310.6082107878. The cubic root of 640626888 is about 862.0551569546.

The spelling of 640626888 in words is "six hundred forty million, six hundred twenty-six thousand, eight hundred eighty-eight".