78765643688 has 8 divisors (see below), whose sum is σ = 147685581930. Its totient is φ = 39382821840.

The previous prime is 78765643681. The next prime is 78765643739. The reversal of 78765643688 is 88634656787.

It can be written as a sum of positive squares in only one way, i.e., 55874558884 + 22891084804 = 236378^2 + 151298^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (78765643681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4922852723 + ... + 4922852738.

Almost surely, 2^78765643688 is an apocalyptic number.

It is an amenable number.

78765643688 is a deficient number, since it is larger than the sum of its proper divisors (68919938242).

78765643688 is a wasteful number, since it uses less digits than its factorization.

78765643688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9845705467 (or 9845705463 counting only the distinct ones).

The product of its digits is 325140480, while the sum is 68.

The spelling of 78765643688 in words is "seventy-eight billion, seven hundred sixty-five million, six hundred forty-three thousand, six hundred eighty-eight".