78847931 has 2 divisors, whose sum is σ = 78847932. Its totient is φ = 78847930.

The previous prime is 78847907. The next prime is 78847943. The reversal of 78847931 is 13974887.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78847931 is a prime.

It is a super-2 number, since 2×78847931² = 12433992445961522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78847981) 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, 39423965 + 39423966.

It is an arithmetic number, because the mean of its divisors is an integer number (39423966).

Almost surely, 2^78847931 is an apocalyptic number.

78847931 is a deficient number, since it is larger than the sum of its proper divisors (1).

78847931 is an equidigital number, since it uses as much as digits as its factorization.

78847931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 338688, while the sum is 47.

The square root of 78847931 is about 8879.6357470338. The cubic root of 78847931 is about 428.8085477935.

The spelling of 78847931 in words is "seventy-eight million, eight hundred forty-seven thousand, nine hundred thirty-one".