21212333 has 4 divisors (see below), whose sum is σ = 21233568. Its totient is φ = 21191100.

The previous prime is 21212297. The next prime is 21212353. The reversal of 21212333 is 33321212.

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 cyclic number.

It is not a de Polignac number, because 21212333 - 2⁸ = 21212077 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9041 + ... + 11142.

It is an arithmetic number, because the mean of its divisors is an integer number (5308392).

Almost surely, 2^21212333 is an apocalyptic number.

It is an amenable number.

21212333 is a deficient number, since it is larger than the sum of its proper divisors (21235).

21212333 is a wasteful number, since it uses less digits than its factorization.

21212333 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21234.

The product of its digits is 216, while the sum is 17.

The square root of 21212333 is about 4605.6848567830. The cubic root of 21212333 is about 276.8191593332.

Adding to 21212333 its reverse (33321212), we get a palindrome (54533545).

The spelling of 21212333 in words is "twenty-one million, two hundred twelve thousand, three hundred thirty-three".