23531 has 2 divisors, whose sum is σ = 23532. Its totient is φ = 23530.

The previous prime is 23509. The next prime is 23537. The reversal of 23531 is 13532.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23531 is a prime.

It is a super-2 number, since 2×23531² = 1107415922, which contains 22 as substring.

It is a Chen prime.

It is equal to p₂₆₁₅ and since 23531 and 2615 have the same sum of digits, it is a Honaker prime.

It is a nialpdrome in base 13.

It is not a weakly prime, because it can be changed into another prime (23537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11765 + 11766.

It is an arithmetic number, because the mean of its divisors is an integer number (11766).

2²³⁵³¹ is an apocalyptic number.

23531 is a deficient number, since it is larger than the sum of its proper divisors (1).

23531 is an equidigital number, since it uses as much as digits as its factorization.

23531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90, while the sum is 14.

The square root of 23531 is about 153.3981746958. The cubic root of 23531 is about 28.6558609595.

Subtracting from 23531 its reverse (13532), we obtain a palindrome (9999).

The spelling of 23531 in words is "twenty-three thousand, five hundred thirty-one".