78816931 has 2 divisors, whose sum is σ = 78816932. Its totient is φ = 78816930.

The previous prime is 78816923. The next prime is 78816971. The reversal of 78816931 is 13961887.

It is a weak prime.

It is an emirp because it is prime and its reverse (13961887) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78816931 - 2³ = 78816923 is a prime.

It is a super-2 number, since 2×78816931² = 12424217224517522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78816901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39408465 + 39408466.

It is an arithmetic number, because the mean of its divisors is an integer number (39408466).

Almost surely, 2^78816931 is an apocalyptic number.

78816931 is a deficient number, since it is larger than the sum of its proper divisors (1).

78816931 is an equidigital number, since it uses as much as digits as its factorization.

78816931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 43.

The square root of 78816931 is about 8877.8900083297. The cubic root of 78816931 is about 428.7523433702.

The spelling of 78816931 in words is "seventy-eight million, eight hundred sixteen thousand, nine hundred thirty-one".