18356161 has 4 divisors (see below), whose sum is σ = 18562500. Its totient is φ = 18149824.

The previous prime is 18356137. The next prime is 18356207. The reversal of 18356161 is 16165381.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9265936 + 9090225 = 3044^2 + 3015^2 .

It is a cyclic number.

It is not a de Polignac number, because 18356161 - 2¹⁷ = 18225089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18356131) 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, 103036 + ... + 103213.

It is an arithmetic number, because the mean of its divisors is an integer number (4640625).

Almost surely, 2^18356161 is an apocalyptic number.

It is an amenable number.

18356161 is a deficient number, since it is larger than the sum of its proper divisors (206339).

18356161 is an equidigital number, since it uses as much as digits as its factorization.

18356161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206338.

The product of its digits is 4320, while the sum is 31.

The square root of 18356161 is about 4284.4090607691. The cubic root of 18356161 is about 263.7913918701.

The spelling of 18356161 in words is "eighteen million, three hundred fifty-six thousand, one hundred sixty-one".