91131492798989 has 4 divisors (see below), whose sum is σ = 91215023040960. Its totient is φ = 91047962557020.

The previous prime is 91131492798943. The next prime is 91131492799031. The reversal of 91131492798989 is 98989729413119.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 91131492798989 - 2²⁰ = 91131491750413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91131492798589) 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, 41765119349 + ... + 41765121530.

It is an arithmetic number, because the mean of its divisors is an integer number (22803755760240).

Almost surely, 2^{91131492798989} is an apocalyptic number.

It is an amenable number.

91131492798989 is a deficient number, since it is larger than the sum of its proper divisors (83530241971).

91131492798989 is a wasteful number, since it uses less digits than its factorization.

91131492798989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83530241970.

The product of its digits is 634894848, while the sum is 80.

The spelling of 91131492798989 in words is "ninety-one trillion, one hundred thirty-one billion, four hundred ninety-two million, seven hundred ninety-eight thousand, nine hundred eighty-nine".