768799991 has 2 divisors, whose sum is σ = 768799992. Its totient is φ = 768799990.

The previous prime is 768799963. The next prime is 768800003. The reversal of 768799991 is 199997867.

It is a strong prime.

It is an emirp because it is prime and its reverse (199997867) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-768799991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (768799951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 384399995 + 384399996.

It is an arithmetic number, because the mean of its divisors is an integer number (384399996).

Almost surely, 2^768799991 is an apocalyptic number.

768799991 is a deficient number, since it is larger than the sum of its proper divisors (1).

768799991 is an equidigital number, since it uses as much as digits as its factorization.

768799991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15431472, while the sum is 65.

The square root of 768799991 is about 27727.2427587021. The cubic root of 768799991 is about 916.0892563019.

The spelling of 768799991 in words is "seven hundred sixty-eight million, seven hundred ninety-nine thousand, nine hundred ninety-one".