21122321 has 4 divisors (see below), whose sum is σ = 23042544. Its totient is φ = 19202100.

The previous prime is 21122291. The next prime is 21122323. The reversal of 21122321 is 12322112.

It is a happy number.

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 21122321 - 2²² = 16928017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21122296 and 21122305.

It is not an unprimeable number, because it can be changed into a prime (21122323) 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, 960095 + ... + 960116.

It is an arithmetic number, because the mean of its divisors is an integer number (5760636).

Almost surely, 2^21122321 is an apocalyptic number.

It is an amenable number.

21122321 is a deficient number, since it is larger than the sum of its proper divisors (1920223).

21122321 is a wasteful number, since it uses less digits than its factorization.

21122321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1920222.

The product of its digits is 48, while the sum is 14.

The square root of 21122321 is about 4595.9026316927. The cubic root of 21122321 is about 276.4270545191.

Adding to 21122321 its reverse (12322112), we get a palindrome (33444433).

The spelling of 21122321 in words is "twenty-one million, one hundred twenty-two thousand, three hundred twenty-one".