23281 has 4 divisors (see below), whose sum is σ = 24064. Its totient is φ = 22500.

The previous prime is 23279. The next prime is 23291. The reversal of 23281 is 18232.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a 4-Lehmer number, since φ(23281) divides (23281-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 23281 - 2¹ = 23279 is a prime.

It is a super-2 number, since 2×23281² = 1084009922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (23201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 345 + ... + 406.

It is an arithmetic number, because the mean of its divisors is an integer number (6016).

2²³²⁸¹ is an apocalyptic number.

23281 is the 97-th centered pentagonal number.

It is an amenable number.

23281 is a deficient number, since it is larger than the sum of its proper divisors (783).

23281 is an equidigital number, since it uses as much as digits as its factorization.

23281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 782.

The product of its digits is 96, while the sum is 16.

The square root of 23281 is about 152.5811259626. The cubic root of 23281 is about 28.5540167721.

It can be divided in two parts, 232 and 81, that added together give a palindrome (313).

The spelling of 23281 in words is "twenty-three thousand, two hundred eighty-one".