18858161 has 4 divisors (see below), whose sum is σ = 21552192. Its totient is φ = 16164132.

The previous prime is 18858157. The next prime is 18858173. The reversal of 18858161 is 16185881.

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: 16185881 = 281 ⋅57601.

It is a cyclic number.

It is not a de Polignac number, because 18858161 - 2² = 18858157 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18854161) 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, 1347005 + ... + 1347018.

It is an arithmetic number, because the mean of its divisors is an integer number (5388048).

Almost surely, 2^18858161 is an apocalyptic number.

It is an amenable number.

18858161 is a deficient number, since it is larger than the sum of its proper divisors (2694031).

18858161 is an equidigital number, since it uses as much as digits as its factorization.

18858161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2694030.

The product of its digits is 15360, while the sum is 38.

The square root of 18858161 is about 4342.5984156954. The cubic root of 18858161 is about 266.1744996678.

The spelling of 18858161 in words is "eighteen million, eight hundred fifty-eight thousand, one hundred sixty-one".