11556221 has 2 divisors, whose sum is σ = 11556222. Its totient is φ = 11556220.

The previous prime is 11556197. The next prime is 11556257. The reversal of 11556221 is 12265511.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8265625 + 3290596 = 2875^2 + 1814^2 .

It is an emirp because it is prime and its reverse (12265511) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11556221 - 2⁶ = 11556157 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11546221) 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, 5778110 + 5778111.

It is an arithmetic number, because the mean of its divisors is an integer number (5778111).

Almost surely, 2^11556221 is an apocalyptic number.

It is an amenable number.

11556221 is a deficient number, since it is larger than the sum of its proper divisors (1).

11556221 is an equidigital number, since it uses as much as digits as its factorization.

11556221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 600, while the sum is 23.

The square root of 11556221 is about 3399.4442192806. Note that the first 3 decimals coincide. The cubic root of 11556221 is about 226.0851025205.

The spelling of 11556221 in words is "eleven million, five hundred fifty-six thousand, two hundred twenty-one".