23581 has 2 divisors, whose sum is σ = 23582. Its totient is φ = 23580.

The previous prime is 23567. The next prime is 23593. The reversal of 23581 is 18532.

It is a happy number.

23581 is nontrivially palindromic in base 2.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17956 + 5625 = 134^2 + 75^2 .

It is a cyclic number.

It is not a de Polignac number, because 23581 - 2⁵ = 23549 is a prime.

It is a super-2 number, since 2×23581² = 1112127122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11790 + 11791.

It is an arithmetic number, because the mean of its divisors is an integer number (11791).

2²³⁵⁸¹ is an apocalyptic number.

It is an amenable number.

23581 is a deficient number, since it is larger than the sum of its proper divisors (1).

23581 is an equidigital number, since it uses as much as digits as its factorization.

23581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 240, while the sum is 19.

The square root of 23581 is about 153.5610627731. The cubic root of 23581 is about 28.6761431322.

The spelling of 23581 in words is "twenty-three thousand, five hundred eighty-one".