12726221 has 2 divisors, whose sum is σ = 12726222. Its totient is φ = 12726220.

The previous prime is 12726179. The next prime is 12726223. The reversal of 12726221 is 12262721.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12180100 + 546121 = 3490^2 + 739^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12726221 is a prime.

It is a Sophie Germain prime.

Together with 12726223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12726223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6363110 + 6363111.

It is an arithmetic number, because the mean of its divisors is an integer number (6363111).

Almost surely, 2^12726221 is an apocalyptic number.

It is an amenable number.

12726221 is a deficient number, since it is larger than the sum of its proper divisors (1).

12726221 is an equidigital number, since it uses as much as digits as its factorization.

12726221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 672, while the sum is 23.

The square root of 12726221 is about 3567.3829343091. The cubic root of 12726221 is about 233.4711129584.

Adding to 12726221 its reverse (12262721), we get a palindrome (24988942).

The spelling of 12726221 in words is "twelve million, seven hundred twenty-six thousand, two hundred twenty-one".