91991172092 has 6 divisors (see below), whose sum is σ = 160984551168. Its totient is φ = 45995586044.

The previous prime is 91991172079. The next prime is 91991172121. The reversal of 91991172092 is 29027119919.

It is a self number, because there is not a number n which added to its sum of digits gives 91991172092.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11498896508 + ... + 11498896515.

It is an arithmetic number, because the mean of its divisors is an integer number (26830758528).

Almost surely, 2^91991172092 is an apocalyptic number.

It is an amenable number.

91991172092 is a deficient number, since it is larger than the sum of its proper divisors (68993379076).

91991172092 is a wasteful number, since it uses less digits than its factorization.

91991172092 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22997793027 (or 22997793025 counting only the distinct ones).

The product of its (nonzero) digits is 183708, while the sum is 50.

The spelling of 91991172092 in words is "ninety-one billion, nine hundred ninety-one million, one hundred seventy-two thousand, ninety-two".