21333223 has 4 divisors (see below), whose sum is σ = 21378240. Its totient is φ = 21288208.

The previous prime is 21333199. The next prime is 21333251. The reversal of 21333223 is 32233312.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21333223 - 2⁹ = 21332711 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21333223.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21333023) 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, 21790 + ... + 22747.

It is an arithmetic number, because the mean of its divisors is an integer number (5344560).

Almost surely, 2^21333223 is an apocalyptic number.

21333223 is a deficient number, since it is larger than the sum of its proper divisors (45017).

21333223 is an equidigital number, since it uses as much as digits as its factorization.

21333223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45016.

The product of its digits is 648, while the sum is 19.

The square root of 21333223 is about 4618.7902095679. The cubic root of 21333223 is about 277.3440316091.

Adding to 21333223 its reverse (32233312), we get a palindrome (53566535).

It can be divided in two parts, 2133 and 3223, that added together give a triangular number (5356 = T₁₀₃).

The spelling of 21333223 in words is "twenty-one million, three hundred thirty-three thousand, two hundred twenty-three".