18461 has 2 divisors, whose sum is σ = 18462. Its totient is φ = 18460.

The previous prime is 18457. The next prime is 18481. The reversal of 18461 is 16481.

It is an a-pointer prime, because the next prime (18481) can be obtained adding 18461 to its sum of digits (20).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11236 + 7225 = 106^2 + 85^2 .

It is an emirp because it is prime and its reverse (16481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18461 - 2² = 18457 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a nialpdrome in base 13.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9230 + 9231.

It is an arithmetic number, because the mean of its divisors is an integer number (9231).

2¹⁸⁴⁶¹ is an apocalyptic number.

It is an amenable number.

18461 is a deficient number, since it is larger than the sum of its proper divisors (1).

18461 is an equidigital number, since it uses as much as digits as its factorization.

18461 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 20.

The square root of 18461 is about 135.8712625981. The cubic root of 18461 is about 26.4292643041.

Adding to 18461 its sum of digits (20), we get a palindrome (18481).

The spelling of 18461 in words is "eighteen thousand, four hundred sixty-one".