13221216 has 72 divisors (see below), whose sum is σ = 38918880. Its totient is φ = 4252416.

The previous prime is 13221209. The next prime is 13221227. The reversal of 13221216 is 61212231.

13221216 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7561 + ... + 9143.

It is an arithmetic number, because the mean of its divisors is an integer number (540540).

Almost surely, 2^13221216 is an apocalyptic number.

13221216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 13221216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19459440).

13221216 is an abundant number, since it is smaller than the sum of its proper divisors (25697664).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

13221216 is a wasteful number, since it uses less digits than its factorization.

13221216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1628 (or 1617 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 13221216 is about 3636.0990085530. The cubic root of 13221216 is about 236.4596995934.

Adding to 13221216 its reverse (61212231), we get a palindrome (74433447).

The spelling of 13221216 in words is "thirteen million, two hundred twenty-one thousand, two hundred sixteen".