18541 has 2 divisors, whose sum is σ = 18542. Its totient is φ = 18540.

The previous prime is 18539. The next prime is 18553. The reversal of 18541 is 14581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15625 + 2916 = 125^2 + 54^2 .

It is a cyclic number.

It is not a de Polignac number, because 18541 - 2¹ = 18539 is a prime.

Together with 18539, it forms a pair of twin primes.

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

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9270 + 9271.

It is an arithmetic number, because the mean of its divisors is an integer number (9271).

2¹⁸⁵⁴¹ is an apocalyptic number.

It is an amenable number.

18541 is a deficient number, since it is larger than the sum of its proper divisors (1).

18541 is an equidigital number, since it uses as much as digits as its factorization.

18541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 160, while the sum is 19.

The square root of 18541 is about 136.1653406708. The cubic root of 18541 is about 26.4673860082.

Subtracting from 18541 its product of digits (160), we obtain a palindrome (18381).

The spelling of 18541 in words is "eighteen thousand, five hundred forty-one".