13221221 has 16 divisors (see below), whose sum is σ = 14999040. Its totient is φ = 11568960.

The previous prime is 13221209. The next prime is 13221227. The reversal of 13221221 is 12212231.

It is a happy number.

It is not a de Polignac number, because 13221221 - 2¹⁴ = 13204837 is a prime.

It is a super-3 number, since 3×13221221³ (a number of 22 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 13221196 and 13221205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13221227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21050 + ... + 21668.

It is an arithmetic number, because the mean of its divisors is an integer number (937440).

Almost surely, 2^13221221 is an apocalyptic number.

It is an amenable number.

13221221 is a deficient number, since it is larger than the sum of its proper divisors (1777819).

13221221 is a wasteful number, since it uses less digits than its factorization.

13221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716.

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

The square root of 13221221 is about 3636.0996961030. The cubic root of 13221221 is about 236.4597294015.

Adding to 13221221 its reverse (12212231), we get a palindrome (25433452).

The spelling of 13221221 in words is "thirteen million, two hundred twenty-one thousand, two hundred twenty-one".