91856798185 has 4 divisors (see below), whose sum is σ = 110228157828. Its totient is φ = 73485438544.

The previous prime is 91856798093. The next prime is 91856798219. The reversal of 91856798185 is 58189765819.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 28575873936 + 63280924249 = 169044^2 + 251557^2 .

It is a cyclic number.

It is not a de Polignac number, because 91856798185 - 2⁹ = 91856797673 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91856798185.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9185679814 + ... + 9185679823.

It is an arithmetic number, because the mean of its divisors is an integer number (27557039457).

Almost surely, 2^91856798185 is an apocalyptic number.

It is an amenable number.

91856798185 is a deficient number, since it is larger than the sum of its proper divisors (18371359643).

91856798185 is a wasteful number, since it uses less digits than its factorization.

91856798185 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18371359642.

The product of its digits is 43545600, while the sum is 67.

The spelling of 91856798185 in words is "ninety-one billion, eight hundred fifty-six million, seven hundred ninety-eight thousand, one hundred eighty-five".