12111221 has 2 divisors, whose sum is σ = 12111222. Its totient is φ = 12111220.

The previous prime is 12111217. The next prime is 12111263. The reversal of 12111221 is 12211121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9424900 + 2686321 = 3070^2 + 1639^2 .

It is a cyclic number.

It is not a de Polignac number, because 12111221 - 2² = 12111217 is a prime.

It is a super-2 number, since 2×12111221² = 293363348221682, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12111521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6055610 + 6055611.

It is an arithmetic number, because the mean of its divisors is an integer number (6055611).

Almost surely, 2^12111221 is an apocalyptic number.

It is an amenable number.

12111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

12111221 is an equidigital number, since it uses as much as digits as its factorization.

12111221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8, while the sum is 11.

The square root of 12111221 is about 3480.1179577710. The cubic root of 12111221 is about 229.6479870420.

Adding to 12111221 its reverse (12211121), we get a palindrome (24322342).

The spelling of 12111221 in words is "twelve million, one hundred eleven thousand, two hundred twenty-one".