640116978 has 16 divisors (see below), whose sum is σ = 1280512800. Its totient is φ = 213325856.

The previous prime is 640116947. The next prime is 640116989. The reversal of 640116978 is 879611046.

640116978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon 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, 29326 + ... + 46262.

It is an arithmetic number, because the mean of its divisors is an integer number (80032050).

Almost surely, 2^640116978 is an apocalyptic number.

640116978 is an abundant number, since it is smaller than the sum of its proper divisors (640395822).

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

640116978 is a wasteful number, since it uses less digits than its factorization.

640116978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23241.

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 640116978 is about 25300.5331564376. The cubic root of 640116978 is about 861.8263772853.

The spelling of 640116978 in words is "six hundred forty million, one hundred sixteen thousand, nine hundred seventy-eight".