640878064846 has 4 divisors (see below), whose sum is σ = 961317097272. Its totient is φ = 320439032422.

The previous prime is 640878064811. The next prime is 640878064889. The reversal of 640878064846 is 648460878046.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160219516210 + ... + 160219516213.

It is an arithmetic number, because the mean of its divisors is an integer number (240329274318).

Almost surely, 2^640878064846 is an apocalyptic number.

640878064846 is a deficient number, since it is larger than the sum of its proper divisors (320439032426).

640878064846 is a wasteful number, since it uses less digits than its factorization.

640878064846 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320439032425.

The product of its (nonzero) digits is 49545216, while the sum is 61.

The spelling of 640878064846 in words is "six hundred forty billion, eight hundred seventy-eight million, sixty-four thousand, eight hundred forty-six".