18161181 has 6 divisors (see below), whose sum is σ = 26232830. Its totient is φ = 12107448.

The previous prime is 18161177. The next prime is 18161183. The reversal of 18161181 is 18116181.

It can be written as a sum of positive squares in only one way, i.e., 17089956 + 1071225 = 4134^2 + 1035^2 .

It is not a de Polignac number, because 18161181 - 2² = 18161177 is a prime.

It is a super-2 number, since 2×18161181² = 659656990629522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18161183) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1008946 + ... + 1008963.

Almost surely, 2^18161181 is an apocalyptic number.

It is an amenable number.

18161181 is a deficient number, since it is larger than the sum of its proper divisors (8071649).

18161181 is a wasteful number, since it uses less digits than its factorization.

18161181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2017915 (or 2017912 counting only the distinct ones).

The product of its digits is 384, while the sum is 27.

The square root of 18161181 is about 4261.5937159706. The cubic root of 18161181 is about 262.8540637157.

The spelling of 18161181 in words is "eighteen million, one hundred sixty-one thousand, one hundred eighty-one".