21213233 has 8 divisors (see below), whose sum is σ = 21772608. Its totient is φ = 20656944.

The previous prime is 21213193. The next prime is 21213251. The reversal of 21213233 is 33231212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21213233 - 2⁸ = 21212977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21213293) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20435 + ... + 21447.

It is an arithmetic number, because the mean of its divisors is an integer number (2721576).

It is a self-describing number.

Almost surely, 2^21213233 is an apocalyptic number.

It is an amenable number.

21213233 is a deficient number, since it is larger than the sum of its proper divisors (559375).

21213233 is a wasteful number, since it uses less digits than its factorization.

21213233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1543.

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

The square root of 21213233 is about 4605.7825610856. The cubic root of 21213233 is about 276.8230742526.

Adding to 21213233 its reverse (33231212), we get a palindrome (54444445).

The spelling of 21213233 in words is "twenty-one million, two hundred thirteen thousand, two hundred thirty-three".