78816431 has 2 divisors, whose sum is σ = 78816432. Its totient is φ = 78816430.

The previous prime is 78816383. The next prime is 78816449. The reversal of 78816431 is 13461887.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78816431 is a prime.

It is a super-2 number, since 2×78816431² = 12424059591155522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78816481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39408215 + 39408216.

It is an arithmetic number, because the mean of its divisors is an integer number (39408216).

Almost surely, 2^78816431 is an apocalyptic number.

78816431 is a deficient number, since it is larger than the sum of its proper divisors (1).

78816431 is an equidigital number, since it uses as much as digits as its factorization.

78816431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32256, while the sum is 38.

The square root of 78816431 is about 8877.8618484408. The cubic root of 78816431 is about 428.7514367265.

The spelling of 78816431 in words is "seventy-eight million, eight hundred sixteen thousand, four hundred thirty-one".