91191894465 has 128 divisors (see below), whose sum is σ = 179719372800. Its totient is φ = 38590110720.

The previous prime is 91191894461. The next prime is 91191894473. The reversal of 91191894465 is 56449819119.

It is not a de Polignac number, because 91191894465 - 2² = 91191894461 is a prime.

It is a super-2 number, since 2×91191894465² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (91191894461) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 10284624 + ... + 10293486.

It is an arithmetic number, because the mean of its divisors is an integer number (1404057600).

Almost surely, 2^91191894465 is an apocalyptic number.

It is an amenable number.

91191894465 is a deficient number, since it is larger than the sum of its proper divisors (88527478335).

91191894465 is a wasteful number, since it uses less digits than its factorization.

91191894465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9047.

The product of its digits is 2799360, while the sum is 57.

The spelling of 91191894465 in words is "ninety-one billion, one hundred ninety-one million, eight hundred ninety-four thousand, four hundred sixty-five".