21321223 has 16 divisors (see below), whose sum is σ = 27129600. Its totient is φ = 16611000.

The previous prime is 21321217. The next prime is 21321263. The reversal of 21321223 is 32212312.

It is not a de Polignac number, because 21321223 - 2⁵ = 21321191 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21321197 and 21321206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 948 + ... + 6598.

It is an arithmetic number, because the mean of its divisors is an integer number (1695600).

Almost surely, 2^21321223 is an apocalyptic number.

21321223 is a deficient number, since it is larger than the sum of its proper divisors (5808377).

21321223 is an equidigital number, since it uses as much as digits as its factorization.

21321223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5683 (or 5669 counting only the distinct ones).

The product of its digits is 144, while the sum is 16.

The square root of 21321223 is about 4617.4909853729. The cubic root of 21321223 is about 277.2920195806.

Adding to 21321223 its reverse (32212312), we get a palindrome (53533535).

The spelling of 21321223 in words is "twenty-one million, three hundred twenty-one thousand, two hundred twenty-three".