13211221 has 4 divisors (see below), whose sum is σ = 13435200. Its totient is φ = 12987244.

The previous prime is 13211207. The next prime is 13211243. The reversal of 13211221 is 12211231.

13211221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 13211221 - 2¹¹ = 13209173 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13211201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111901 + ... + 112018.

It is an arithmetic number, because the mean of its divisors is an integer number (3358800).

Almost surely, 2^13211221 is an apocalyptic number.

It is an amenable number.

13211221 is a deficient number, since it is larger than the sum of its proper divisors (223979).

13211221 is an equidigital number, since it uses as much as digits as its factorization.

13211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223978.

The product of its digits is 24, while the sum is 13.

The square root of 13211221 is about 3634.7243361774. The cubic root of 13211221 is about 236.4000981540.

Adding to 13211221 its reverse (12211231), we get a palindrome (25422452).

The spelling of 13211221 in words is "thirteen million, two hundred eleven thousand, two hundred twenty-one".