12711221 has 2 divisors, whose sum is σ = 12711222. Its totient is φ = 12711220.

The previous prime is 12711217. The next prime is 12711227. The reversal of 12711221 is 12211721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10491121 + 2220100 = 3239^2 + 1490^2 .

It is an emirp because it is prime and its reverse (12211721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12711221 - 2² = 12711217 is a prime.

It is a Sophie Germain prime.

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 12711221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12711227) 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, 6355610 + 6355611.

It is an arithmetic number, because the mean of its divisors is an integer number (6355611).

Almost surely, 2^12711221 is an apocalyptic number.

It is an amenable number.

12711221 is a deficient number, since it is larger than the sum of its proper divisors (1).

12711221 is an equidigital number, since it uses as much as digits as its factorization.

12711221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56, while the sum is 17.

The square root of 12711221 is about 3565.2799329085. The cubic root of 12711221 is about 233.3793485212.

Adding to 12711221 its reverse (12211721), we get a palindrome (24922942).

Subtracting from 12711221 its reverse (12211721), we obtain a triangular number (499500 = T₉₉₉).

The spelling of 12711221 in words is "twelve million, seven hundred eleven thousand, two hundred twenty-one".