91081091 has 2 divisors, whose sum is σ = 91081092. Its totient is φ = 91081090.

The previous prime is 91081063. The next prime is 91081097. The reversal of 91081091 is 19018019.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91081091 is a prime.

It is not a weakly prime, because it can be changed into another prime (91081097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45540545 + 45540546.

It is an arithmetic number, because the mean of its divisors is an integer number (45540546).

Almost surely, 2^91081091 is an apocalyptic number.

91081091 is a deficient number, since it is larger than the sum of its proper divisors (1).

91081091 is an equidigital number, since it uses as much as digits as its factorization.

91081091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 91081091 is about 9543.6413909996. The cubic root of 91081091 is about 449.9277101984.

The spelling of 91081091 in words is "ninety-one million, eighty-one thousand, ninety-one".