78717158640 has 80 divisors (see below), whose sum is σ = 271136887200. Its totient is φ = 20991241728.

The previous prime is 78717158609. The next prime is 78717158651. The reversal of 78717158640 is 4685171787.

78717158640 is a `hidden beast` number, since 7 + 8 + 7 + 17 + 1 + 586 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

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, 18219405 + ... + 18223724.

It is an arithmetic number, because the mean of its divisors is an integer number (3389211090).

Almost surely, 2^78717158640 is an apocalyptic number.

It is an amenable number.

78717158640 is an abundant number, since it is smaller than the sum of its proper divisors (192419728560).

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

78717158640 is a wasteful number, since it uses less digits than its factorization.

78717158640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36443151 (or 36443139 counting only the distinct ones).

The product of its (nonzero) digits is 2634240, while the sum is 54.

The spelling of 78717158640 in words is "seventy-eight billion, seven hundred seventeen million, one hundred fifty-eight thousand, six hundred forty".