78717309568 has 64 divisors (see below), whose sum is σ = 161245873800. Its totient is φ = 38261403648.

The previous prime is 78717309553. The next prime is 78717309569. The reversal of 78717309568 is 86590371787.

It can be written as a sum of positive squares in 4 ways, for example, as 78709424704 + 7884864 = 280552^2 + 2808^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (78717309569) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 686230 + ... + 792682.

Almost surely, 2^78717309568 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78717309568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80622936900).

78717309568 is an abundant number, since it is smaller than the sum of its proper divisors (82528564232).

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

78717309568 is a wasteful number, since it uses less digits than its factorization.

78717309568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106629 (or 106617 counting only the distinct ones).

The product of its (nonzero) digits is 17781120, while the sum is 61.

The spelling of 78717309568 in words is "seventy-eight billion, seven hundred seventeen million, three hundred nine thousand, five hundred sixty-eight".