10991860091 has 4 divisors (see below), whose sum is σ = 10992086784. Its totient is φ = 10991633400.

The previous prime is 10991860043. The next prime is 10991860097. The reversal of 10991860091 is 19006819901.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-10991860091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (10991860097) 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, 7940 + ... + 148481.

It is an arithmetic number, because the mean of its divisors is an integer number (2748021696).

Almost surely, 2^10991860091 is an apocalyptic number.

10991860091 is a deficient number, since it is larger than the sum of its proper divisors (226693).

10991860091 is an equidigital number, since it uses as much as digits as its factorization.

10991860091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226692.

The product of its (nonzero) digits is 34992, while the sum is 44.

The spelling of 10991860091 in words is "ten billion, nine hundred ninety-one million, eight hundred sixty thousand, ninety-one".