640306788 has 48 divisors (see below), whose sum is σ = 1631520576. Its totient is φ = 193836160.

The previous prime is 640306781. The next prime is 640306801. The reversal of 640306788 is 887603046.

It is not an unprimeable number, because it can be changed into a prime (640306781) 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 15 ways as a sum of consecutive naturals, for example, 179470 + ... + 183002.

It is an arithmetic number, because the mean of its divisors is an integer number (33990012).

Almost surely, 2^640306788 is an apocalyptic number.

It is an amenable number.

640306788 is an abundant number, since it is smaller than the sum of its proper divisors (991213788).

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

640306788 is a wasteful number, since it uses less digits than its factorization.

640306788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4924 (or 4922 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 42.

The square root of 640306788 is about 25304.2839851279. The cubic root of 640306788 is about 861.9115529142.

The spelling of 640306788 in words is "six hundred forty million, three hundred six thousand, seven hundred eighty-eight".