11161155661 has 4 divisors (see below), whose sum is σ = 11161554172. Its totient is φ = 11160757152.

The previous prime is 11161155647. The next prime is 11161155667. The reversal of 11161155661 is 16655116111.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16655116111 = 4157 ⋅4006523.

It can be written as a sum of positive squares in 2 ways, for example, as 10690526025 + 470629636 = 103395^2 + 21694^2 .

It is a cyclic number.

It is not a de Polignac number, because 11161155661 - 2³¹ = 9013672013 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 (11161155667) 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, 153786 + ... + 214411.

It is an arithmetic number, because the mean of its divisors is an integer number (2790388543).

Almost surely, 2^11161155661 is an apocalyptic number.

It is an amenable number.

11161155661 is a deficient number, since it is larger than the sum of its proper divisors (398511).

11161155661 is an equidigital number, since it uses as much as digits as its factorization.

11161155661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398510.

The product of its digits is 5400, while the sum is 34.

The spelling of 11161155661 in words is "eleven billion, one hundred sixty-one million, one hundred fifty-five thousand, six hundred sixty-one".