21233 has 4 divisors (see below), whose sum is σ = 22500. Its totient is φ = 19968.

The previous prime is 21227. The next prime is 21247. The reversal of 21233 is 33212.

21233 = 27² + 28² + ... + 43².

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12769 + 8464 = 113^2 + 92^2 .

It is a cyclic number.

It is not a de Polignac number, because 21233 - 2⁶ = 21169 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (21283) 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, 608 + ... + 641.

It is an arithmetic number, because the mean of its divisors is an integer number (5625).

2²¹²³³ is an apocalyptic number.

It is an amenable number.

21233 is a deficient number, since it is larger than the sum of its proper divisors (1267).

21233 is a wasteful number, since it uses less digits than its factorization.

21233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1266.

The product of its digits is 36, while the sum is 11.

The square root of 21233 is about 145.7154761856. The cubic root of 21233 is about 27.6909031022.

Adding to 21233 its reverse (33212), we get a palindrome (54445).

It can be divided in two parts, 212 and 33, that multiplied together give a palindrome (6996).

The spelling of 21233 in words is "twenty-one thousand, two hundred thirty-three".