78840791 has 2 divisors, whose sum is σ = 78840792. Its totient is φ = 78840790.

The previous prime is 78840767. The next prime is 78840809. The reversal of 78840791 is 19704887.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78840791 - 2¹⁰ = 78839767 is a 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 (78840721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39420395 + 39420396.

It is an arithmetic number, because the mean of its divisors is an integer number (39420396).

Almost surely, 2^78840791 is an apocalyptic number.

78840791 is a deficient number, since it is larger than the sum of its proper divisors (1).

78840791 is an equidigital number, since it uses as much as digits as its factorization.

78840791 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 78840791 is about 8879.2336944130. The cubic root of 78840791 is about 428.7956039516.

The spelling of 78840791 in words is "seventy-eight million, eight hundred forty thousand, seven hundred ninety-one".