640748670 has 16 divisors (see below), whose sum is σ = 1537796880. Its totient is φ = 170866304.

The previous prime is 640748663. The next prime is 640748687. The reversal of 640748670 is 76847046.

640748670 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

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, 10679115 + ... + 10679174.

It is an arithmetic number, because the mean of its divisors is an integer number (96112305).

Almost surely, 2^640748670 is an apocalyptic number.

640748670 is an abundant number, since it is smaller than the sum of its proper divisors (897048210).

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

640748670 is a wasteful number, since it uses less digits than its factorization.

640748670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21358299.

The product of its (nonzero) digits is 225792, while the sum is 42.

The square root of 640748670 is about 25313.0138466363. The cubic root of 640748670 is about 862.1097785299.

The spelling of 640748670 in words is "six hundred forty million, seven hundred forty-eight thousand, six hundred seventy".