91110091 has 4 divisors (see below), whose sum is σ = 91130832. Its totient is φ = 91089352.

The previous prime is 91110079. The next prime is 91110109. The reversal of 91110091 is 19001119.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19001119 = 29 ⋅655211.

It is a cyclic number.

It is not a de Polignac number, because 91110091 - 2²¹ = 89012939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91110001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 895 + ... + 13528.

It is an arithmetic number, because the mean of its divisors is an integer number (22782708).

Almost surely, 2^91110091 is an apocalyptic number.

91110091 is a deficient number, since it is larger than the sum of its proper divisors (20741).

91110091 is a wasteful number, since it uses less digits than its factorization.

91110091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20740.

The product of its (nonzero) digits is 81, while the sum is 22.

The square root of 91110091 is about 9545.1606062968. The cubic root of 91110091 is about 449.9754570977.

The spelling of 91110091 in words is "ninety-one million, one hundred ten thousand, ninety-one".