21322312221 has 48 divisors (see below), whose sum is σ = 34905523200. Its totient is φ = 11511878112.

The previous prime is 21322312189. The next prime is 21322312223. The reversal of 21322312221 is 12221322312.

It is not a de Polignac number, because 21322312221 - 2⁵ = 21322312189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21322312223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1048476 + ... + 1068618.

It is an arithmetic number, because the mean of its divisors is an integer number (727198400).

Almost surely, 2^21322312221 is an apocalyptic number.

21322312221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21322312221 is a deficient number, since it is larger than the sum of its proper divisors (13583210979).

21322312221 is a wasteful number, since it uses less digits than its factorization.

21322312221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20558 (or 20551 counting only the distinct ones).

The product of its digits is 576, while the sum is 21.

Adding to 21322312221 its reverse (12221322312), we get a palindrome (33543634533).

The spelling of 21322312221 in words is "twenty-one billion, three hundred twenty-two million, three hundred twelve thousand, two hundred twenty-one".