640308894 has 8 divisors (see below), whose sum is σ = 1280617800. Its totient is φ = 213436296.

The previous prime is 640308863. The next prime is 640308899. The reversal of 640308894 is 498803046.

640308894 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

640308894 is an admirable number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640308899) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53359069 + ... + 53359080.

It is an arithmetic number, because the mean of its divisors is an integer number (160077225).

Almost surely, 2^640308894 is an apocalyptic number.

640308894 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

640308894 is a wasteful number, since it uses less digits than its factorization.

640308894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106718154.

The product of its (nonzero) digits is 165888, while the sum is 42.

The square root of 640308894 is about 25304.3255986007. The cubic root of 640308894 is about 861.9124978694.

The spelling of 640308894 in words is "six hundred forty million, three hundred eight thousand, eight hundred ninety-four".