11111111091 has 28 divisors (see below), whose sum is σ = 16812001360. Its totient is φ = 7339397040.

The previous prime is 11111111059. The next prime is 11111111113. The reversal of 11111111091 is 19011111111.

It is not a de Polignac number, because 11111111091 - 2⁵ = 11111111059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11111111491) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 9546 + ... + 149376.

It is an arithmetic number, because the mean of its divisors is an integer number (600428620).

Almost surely, 2^11111111091 is an apocalyptic number.

11111111091 is a deficient number, since it is larger than the sum of its proper divisors (5700890269).

11111111091 is an equidigital number, since it uses as much as digits as its factorization.

11111111091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139958 (or 139943 counting only the distinct ones).

The product of its (nonzero) digits is 9, while the sum is 18.

The spelling of 11111111091 in words is "eleven billion, one hundred eleven million, one hundred eleven thousand, ninety-one".