18161 has 8 divisors (see below), whose sum is σ = 21504. Its totient is φ = 15120.

The previous prime is 18149. The next prime is 18169. The reversal of 18161 is 16181.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18161 - 2⁶ = 18097 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18169) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80 + ... + 206.

It is an arithmetic number, because the mean of its divisors is an integer number (2688).

2¹⁸¹⁶¹ is an apocalyptic number.

18161 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18161 is a deficient number, since it is larger than the sum of its proper divisors (3343).

18161 is a wasteful number, since it uses less digits than its factorization.

18161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151.

The product of its digits is 48, while the sum is 17.

The square root of 18161 is about 134.7627544984. The cubic root of 18161 is about 26.2853190484.

It can be divided in two parts, 181 and 61, that added together give a palindrome (242).

The spelling of 18161 in words is "eighteen thousand, one hundred sixty-one".