12281221 has 2 divisors, whose sum is σ = 12281222. Its totient is φ = 12281220.

The previous prime is 12281207. The next prime is 12281237. The reversal of 12281221 is 12218221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10562500 + 1718721 = 3250^2 + 1311^2 .

It is a cyclic number.

It is not a de Polignac number, because 12281221 - 2¹³ = 12273029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12281251) 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, 6140610 + 6140611.

It is an arithmetic number, because the mean of its divisors is an integer number (6140611).

Almost surely, 2^12281221 is an apocalyptic number.

It is an amenable number.

12281221 is a deficient number, since it is larger than the sum of its proper divisors (1).

12281221 is an equidigital number, since it uses as much as digits as its factorization.

12281221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 128, while the sum is 19.

The square root of 12281221 is about 3504.4573046336. The cubic root of 12281221 is about 230.7174885048.

Adding to 12281221 its reverse (12218221), we get a palindrome (24499442).

The spelling of 12281221 in words is "twelve million, two hundred eighty-one thousand, two hundred twenty-one".