91911779 has 2 divisors, whose sum is σ = 91911780. Its totient is φ = 91911778.

The previous prime is 91911773. The next prime is 91911821. The reversal of 91911779 is 97711919.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91911779 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (91911773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45955889 + 45955890.

It is an arithmetic number, because the mean of its divisors is an integer number (45955890).

Almost surely, 2^91911779 is an apocalyptic number.

91911779 is a deficient number, since it is larger than the sum of its proper divisors (1).

91911779 is an equidigital number, since it uses as much as digits as its factorization.

91911779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35721, while the sum is 44.

The square root of 91911779 is about 9587.0631060821. The cubic root of 91911779 is about 451.2913998895.

The spelling of 91911779 in words is "ninety-one million, nine hundred eleven thousand, seven hundred seventy-nine".