91111091 has 2 divisors, whose sum is σ = 91111092. Its totient is φ = 91111090.

The previous prime is 91111087. The next prime is 91111093. The reversal of 91111091 is 19011119.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91111091 - 2² = 91111087 is a prime.

Together with 91111093, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (91111093) 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, 45555545 + 45555546.

It is an arithmetic number, because the mean of its divisors is an integer number (45555546).

Almost surely, 2^91111091 is an apocalyptic number.

91111091 is a deficient number, since it is larger than the sum of its proper divisors (1).

91111091 is an equidigital number, since it uses as much as digits as its factorization.

91111091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81, while the sum is 23.

The square root of 91111091 is about 9545.2129887185. The cubic root of 91111091 is about 449.9771033618.

The spelling of 91111091 in words is "ninety-one million, one hundred eleven thousand, ninety-one".