13213221 has 16 divisors (see below), whose sum is σ = 20256384. Its totient is φ = 7504704.

The previous prime is 13213159. The next prime is 13213229. The reversal of 13213221 is 12231231.

13213221 is digitally balanced in base 2 and base 8, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 13213221 - 2⁷ = 13213093 is a prime.

13213221 is strictly pandigital in base 8.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 13213221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13213229) 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, 1815 + ... + 5451.

It is an arithmetic number, because the mean of its divisors is an integer number (1266024).

Almost surely, 2^13213221 is an apocalyptic number.

It is an amenable number.

13213221 is a deficient number, since it is larger than the sum of its proper divisors (7043163).

13213221 is a wasteful number, since it uses less digits than its factorization.

13213221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3820.

The product of its digits is 72, while the sum is 15.

The square root of 13213221 is about 3634.9994497936. Note that the first 3 decimals coincide. The cubic root of 13213221 is about 236.4120268102.

Adding to 13213221 its reverse (12231231), we get a palindrome (25444452).

It can be divided in two parts, 132132 and 21, that multiplied together give a palindrome (2774772).

The spelling of 13213221 in words is "thirteen million, two hundred thirteen thousand, two hundred twenty-one".