11331221221 has 2 divisors, whose sum is σ = 11331221222. Its totient is φ = 11331221220.

The previous prime is 11331221207. The next prime is 11331221227. The reversal of 11331221221 is 12212213311.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7763548321 + 3567672900 = 88111^2 + 59730^2 .

It is a cyclic number.

It is not a de Polignac number, because 11331221221 - 2⁷ = 11331221093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11331221227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5665610610 + 5665610611.

It is an arithmetic number, because the mean of its divisors is an integer number (5665610611).

Almost surely, 2^11331221221 is an apocalyptic number.

It is an amenable number.

11331221221 is a deficient number, since it is larger than the sum of its proper divisors (1).

11331221221 is an equidigital number, since it uses as much as digits as its factorization.

11331221221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 19.

Adding to 11331221221 its reverse (12212213311), we get a palindrome (23543434532).

The spelling of 11331221221 in words is "eleven billion, three hundred thirty-one million, two hundred twenty-one thousand, two hundred twenty-one".