18361 has 8 divisors (see below), whose sum is σ = 21824. Its totient is φ = 15120.

The previous prime is 18353. The next prime is 18367. The reversal of 18361 is 16381.

18361 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 18361 - 2³ = 18353 is a prime.

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

It is the 136-th Hogben number.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (18367) by changing a digit.

It is a nontrivial repunit in base 135.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 271 + ... + 331.

It is an arithmetic number, because the mean of its divisors is an integer number (2728).

2¹⁸³⁶¹ is an apocalyptic number.

18361 is the 86-th heptagonal number.

It is an amenable number.

18361 is a deficient number, since it is larger than the sum of its proper divisors (3463).

18361 is an equidigital number, since it uses as much as digits as its factorization.

18361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111.

The product of its digits is 144, while the sum is 19.

The square root of 18361 is about 135.5027674994. The cubic root of 18361 is about 26.3814569817.

The spelling of 18361 in words is "eighteen thousand, three hundred sixty-one".