21222321 has 8 divisors (see below), whose sum is σ = 29209344. Its totient is φ = 13691760.

The previous prime is 21222293. The next prime is 21222343. The reversal of 21222321 is 12322212.

It is a happy number.

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

It is not a de Polignac number, because 21222321 - 2¹⁷ = 21091249 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21222321.

It is not an unprimeable number, because it can be changed into a prime (21222361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114006 + ... + 114191.

It is an arithmetic number, because the mean of its divisors is an integer number (3651168).

Almost surely, 2^21222321 is an apocalyptic number.

It is an amenable number.

21222321 is a deficient number, since it is larger than the sum of its proper divisors (7987023).

21222321 is a wasteful number, since it uses less digits than its factorization.

21222321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228231.

The product of its digits is 96, while the sum is 15.

The square root of 21222321 is about 4606.7690413130. The cubic root of 21222321 is about 276.8626000354.

Adding to 21222321 its reverse (12322212), we get a palindrome (33544533).

The spelling of 21222321 in words is "twenty-one million, two hundred twenty-two thousand, three hundred twenty-one".