78728642664 has 64 divisors (see below), whose sum is σ = 229183136640. Its totient is φ = 22069482240.

The previous prime is 78728642653. The next prime is 78728642689. The reversal of 78728642664 is 46624682787.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 78728642598 and 78728642607.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4412067 + ... + 4429874.

It is an arithmetic number, because the mean of its divisors is an integer number (3580986510).

Almost surely, 2^78728642664 is an apocalyptic number.

It is an amenable number.

78728642664 is an abundant number, since it is smaller than the sum of its proper divisors (150454493976).

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

78728642664 is a wasteful number, since it uses less digits than its factorization.

78728642664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8842010 (or 8842006 counting only the distinct ones).

The product of its digits is 43352064, while the sum is 60.

The spelling of 78728642664 in words is "seventy-eight billion, seven hundred twenty-eight million, six hundred forty-two thousand, six hundred sixty-four".