13251221 has 4 divisors (see below), whose sum is σ = 13273452. Its totient is φ = 13228992.

The previous prime is 13251169. The next prime is 13251233. The reversal of 13251221 is 12215231.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 790321 + 12460900 = 889^2 + 3530^2 .

It is a cyclic number.

It is not a de Polignac number, because 13251221 - 2⁶ = 13251157 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13251221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13251421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10196 + ... + 11421.

It is an arithmetic number, because the mean of its divisors is an integer number (3318363).

Almost surely, 2^13251221 is an apocalyptic number.

It is an amenable number.

13251221 is a deficient number, since it is larger than the sum of its proper divisors (22231).

13251221 is an equidigital number, since it uses as much as digits as its factorization.

13251221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22230.

The product of its digits is 120, while the sum is 17.

The square root of 13251221 is about 3640.2226580252. Note that the first 3 decimals coincide. The cubic root of 13251221 is about 236.6384429302.

Adding to 13251221 its reverse (12215231), we get a palindrome (25466452).

The spelling of 13251221 in words is "thirteen million, two hundred fifty-one thousand, two hundred twenty-one".