21225321 has 24 divisors (see below), whose sum is σ = 34245120. Its totient is φ = 13059792.

The previous prime is 21225317. The next prime is 21225329. The reversal of 21225321 is 12352212.

It is not a de Polignac number, because 21225321 - 2² = 21225317 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21225294 and 21225303.

It is not an unprimeable number, because it can be changed into a prime (21225329) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 201 + ... + 6518.

It is an arithmetic number, because the mean of its divisors is an integer number (1426880).

Almost surely, 2^21225321 is an apocalyptic number.

It is an amenable number.

21225321 is a deficient number, since it is larger than the sum of its proper divisors (13019799).

21225321 is an equidigital number, since it uses as much as digits as its factorization.

21225321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6747 (or 6735 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 21225321 is about 4607.0946376214. The cubic root of 21225321 is about 276.8756452417.

Adding to 21225321 its reverse (12352212), we get a palindrome (33577533).

The spelling of 21225321 in words is "twenty-one million, two hundred twenty-five thousand, three hundred twenty-one".