91011091091 has 4 divisors (see below), whose sum is σ = 91053801384. Its totient is φ = 90968380800.

The previous prime is 91011091051. The next prime is 91011091109. The reversal of 91011091091 is 19019011019.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19019011019 = 56731 ⋅335249.

It is a cyclic number.

It is not a de Polignac number, because 91011091091 - 2³⁴ = 73831221907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91011091051) 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 in 3 ways as a sum of consecutive naturals, for example, 21351950 + ... + 21356211.

It is an arithmetic number, because the mean of its divisors is an integer number (22763450346).

Almost surely, 2^91011091091 is an apocalyptic number.

91011091091 is a deficient number, since it is larger than the sum of its proper divisors (42710293).

91011091091 is a wasteful number, since it uses less digits than its factorization.

91011091091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42710292.

The product of its (nonzero) digits is 729, while the sum is 32.

The spelling of 91011091091 in words is "ninety-one billion, eleven million, ninety-one thousand, ninety-one".