12212221 has 6 divisors (see below), whose sum is σ = 14206110. Its totient is φ = 10467576.

The previous prime is 12212201. The next prime is 12212237. The reversal of 12212221 is 12221221.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 12152196 + 60025 = 3486^2 + 245^2 .

It is not a de Polignac number, because 12212221 - 2⁹ = 12211709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12212201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 124566 + ... + 124663.

It is an arithmetic number, because the mean of its divisors is an integer number (2367685).

Almost surely, 2^12212221 is an apocalyptic number.

It is an amenable number.

12212221 is a deficient number, since it is larger than the sum of its proper divisors (1993889).

12212221 is an equidigital number, since it uses as much as digits as its factorization.

12212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249243 (or 249236 counting only the distinct ones).

The product of its digits is 32, while the sum is 13.

The square root of 12212221 is about 3494.5988324842. The cubic root of 12212221 is about 230.2845941475.

Adding to 12212221 its reverse (12221221), we get a palindrome (24433442).

The spelling of 12212221 in words is "twelve million, two hundred twelve thousand, two hundred twenty-one".