11111091661 has 4 divisors (see below), whose sum is σ = 11177625312. Its totient is φ = 11044558012.

The previous prime is 11111091647. The next prime is 11111091671. The reversal of 11111091661 is 16619011111.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 11111091661 - 2⁷ = 11111091533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111091671) 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, 33266575 + ... + 33266908.

It is an arithmetic number, because the mean of its divisors is an integer number (2794406328).

Almost surely, 2^11111091661 is an apocalyptic number.

It is an amenable number.

11111091661 is a deficient number, since it is larger than the sum of its proper divisors (66533651).

11111091661 is an equidigital number, since it uses as much as digits as its factorization.

11111091661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66533650.

The product of its (nonzero) digits is 324, while the sum is 28.

The spelling of 11111091661 in words is "eleven billion, one hundred eleven million, ninety-one thousand, six hundred sixty-one".