18158161 has 4 divisors (see below), whose sum is σ = 20752192. Its totient is φ = 15564132.

The previous prime is 18158137. The next prime is 18158191. The reversal of 18158161 is 16185181.

It is a happy number.

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: 16185181 = 131 ⋅123551.

It is a cyclic number.

It is not a de Polignac number, because 18158161 - 2²¹ = 16061009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18158191) 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, 1297005 + ... + 1297018.

It is an arithmetic number, because the mean of its divisors is an integer number (5188048).

Almost surely, 2^18158161 is an apocalyptic number.

It is an amenable number.

18158161 is a deficient number, since it is larger than the sum of its proper divisors (2594031).

18158161 is an equidigital number, since it uses as much as digits as its factorization.

18158161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2594030.

The product of its digits is 1920, while the sum is 31.

The square root of 18158161 is about 4261.2393737034. The cubic root of 18158161 is about 262.8394930172.

The spelling of 18158161 in words is "eighteen million, one hundred fifty-eight thousand, one hundred sixty-one".