111665161 has 4 divisors (see below), whose sum is σ = 116520192. Its totient is φ = 106810132.

The previous prime is 111665143. The next prime is 111665171. The reversal of 111665161 is 161566111.

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, and also an emirpimes, since its reverse is a distinct semiprime: 161566111 = 7 ⋅23080873.

It is a cyclic number.

It is not a de Polignac number, because 111665161 - 2⁹ = 111664649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (111665171) 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, 2427481 + ... + 2427526.

It is an arithmetic number, because the mean of its divisors is an integer number (29130048).

Almost surely, 2^111665161 is an apocalyptic number.

It is an amenable number.

111665161 is a deficient number, since it is larger than the sum of its proper divisors (4855031).

111665161 is an equidigital number, since it uses as much as digits as its factorization.

111665161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4855030.

The product of its digits is 1080, while the sum is 28.

The square root of 111665161 is about 10567.1737470338. The cubic root of 111665161 is about 481.5476104630.

The spelling of 111665161 in words is "one hundred eleven million, six hundred sixty-five thousand, one hundred sixty-one".