78616686389 has 2 divisors, whose sum is σ = 78616686390. Its totient is φ = 78616686388.

The previous prime is 78616686361. The next prime is 78616686413. The reversal of 78616686389 is 98368661687.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75387037489 + 3229648900 = 274567^2 + 56830^2 .

It is an emirp because it is prime and its reverse (98368661687) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78616686389 - 2²⁸ = 78348250933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78616686089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39308343194 + 39308343195.

It is an arithmetic number, because the mean of its divisors is an integer number (39308343195).

Almost surely, 2^78616686389 is an apocalyptic number.

It is an amenable number.

78616686389 is a deficient number, since it is larger than the sum of its proper divisors (1).

78616686389 is an equidigital number, since it uses as much as digits as its factorization.

78616686389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 125411328, while the sum is 68.

The spelling of 78616686389 in words is "seventy-eight billion, six hundred sixteen million, six hundred eighty-six thousand, three hundred eighty-nine".