78855918689 has 2 divisors, whose sum is σ = 78855918690. Its totient is φ = 78855918688.

The previous prime is 78855918637. The next prime is 78855918697. The reversal of 78855918689 is 98681955887.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70278010000 + 8577908689 = 265100^2 + 92617^2 .

It is an emirp because it is prime and its reverse (98681955887) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78855918689 - 2¹² = 78855914593 is a prime.

It is not a weakly prime, because it can be changed into another prime (78855918619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39427959344 + 39427959345.

It is an arithmetic number, because the mean of its divisors is an integer number (39427959345).

Almost surely, 2^78855918689 is an apocalyptic number.

It is an amenable number.

78855918689 is a deficient number, since it is larger than the sum of its proper divisors (1).

78855918689 is an equidigital number, since it uses as much as digits as its factorization.

78855918689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 348364800, while the sum is 74.

The spelling of 78855918689 in words is "seventy-eight billion, eight hundred fifty-five million, nine hundred eighteen thousand, six hundred eighty-nine".