11811221 has 2 divisors, whose sum is σ = 11811222. Its totient is φ = 11811220.

The previous prime is 11811203. The next prime is 11811227. The reversal of 11811221 is 12211811.

11811221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11662225 + 148996 = 3415^2 + 386^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11811221 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 11811221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11811227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5905610 + 5905611.

It is an arithmetic number, because the mean of its divisors is an integer number (5905611).

Almost surely, 2^11811221 is an apocalyptic number.

It is an amenable number.

11811221 is a deficient number, since it is larger than the sum of its proper divisors (1).

11811221 is an equidigital number, since it uses as much as digits as its factorization.

11811221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32, while the sum is 17.

The square root of 11811221 is about 3436.7456990589. The cubic root of 11811221 is about 227.7359529172.

The spelling of 11811221 in words is "eleven million, eight hundred eleven thousand, two hundred twenty-one".