21335233 has 12 divisors (see below), whose sum is σ = 22871440. Its totient is φ = 19846296.

The previous prime is 21335231. The next prime is 21335257. The reversal of 21335233 is 33253312.

It is a happy number.

It is not a de Polignac number, because 21335233 - 2¹ = 21335231 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21335231) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 130810 + ... + 130972.

Almost surely, 2^21335233 is an apocalyptic number.

It is an amenable number.

21335233 is a deficient number, since it is larger than the sum of its proper divisors (1536207).

21335233 is an equidigital number, since it uses as much as digits as its factorization.

21335233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348 (or 265 counting only the distinct ones).

The product of its digits is 1620, while the sum is 22.

The square root of 21335233 is about 4619.0077938882. The cubic root of 21335233 is about 277.3527417165.

Adding to 21335233 its reverse (33253312), we get a palindrome (54588545).

The spelling of 21335233 in words is "twenty-one million, three hundred thirty-five thousand, two hundred thirty-three".