13221 has 12 divisors (see below), whose sum is σ = 20748. Its totient is φ = 8064.

The previous prime is 13219. The next prime is 13229. The reversal of 13221 is 12231.

13221 = T₁₈ + T₁₉ + ... + T₄₃.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 900 + 12321 = 30^2 + 111^2 .

It is not a de Polignac number, because 13221 - 2¹ = 13219 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a plaindrome in base 12.

It is a zygodrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13229) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 61 + ... + 173.

It is an arithmetic number, because the mean of its divisors is an integer number (1729).

2¹³²²¹ is an apocalyptic number.

It is an amenable number.

13221 is a deficient number, since it is larger than the sum of its proper divisors (7527).

13221 is a wasteful number, since it uses less digits than its factorization.

13221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132 (or 129 counting only the distinct ones).

The product of its digits is 12, while the sum is 9.

The square root of 13221 is about 114.9826073804. The cubic root of 13221 is about 23.6458411876.

Adding to 13221 its reverse (12231), we get a palindrome (25452).

Subtracting from 13221 its reverse (12231), we obtain a triangular number (990 = T₄₄).

It can be divided in two parts, 132 and 21, that multiplied together give a palindrome (2772).

The spelling of 13221 in words is "thirteen thousand, two hundred twenty-one".