111661161 has 4 divisors (see below), whose sum is σ = 148881552. Its totient is φ = 74440772.

The previous prime is 111661141. The next prime is 111661181. The reversal of 111661161 is 161166111.

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 an interprime number because it is at equal distance from previous prime (111661141) and next prime (111661181).

It is a cyclic number.

It is not a de Polignac number, because 111661161 - 2⁶ = 111661097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (111661111) 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, 18610191 + ... + 18610196.

It is an arithmetic number, because the mean of its divisors is an integer number (37220388).

Almost surely, 2^111661161 is an apocalyptic number.

It is an amenable number.

111661161 is a deficient number, since it is larger than the sum of its proper divisors (37220391).

111661161 is an equidigital number, since it uses as much as digits as its factorization.

111661161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37220390.

The product of its digits is 216, while the sum is 24.

The square root of 111661161 is about 10566.9844799735. The cubic root of 111661161 is about 481.5418604946.

The spelling of 111661161 in words is "one hundred eleven million, six hundred sixty-one thousand, one hundred sixty-one".