12188021 has 2 divisors, whose sum is σ = 12188022. Its totient is φ = 12188020.

The previous prime is 12188017. The next prime is 12188027. The reversal of 12188021 is 12088121.

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., 12180100 + 7921 = 3490^2 + 89^2 .

It is a cyclic number.

It is not a de Polignac number, because 12188021 - 2² = 12188017 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12188027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6094010 + 6094011.

It is an arithmetic number, because the mean of its divisors is an integer number (6094011).

Almost surely, 2^12188021 is an apocalyptic number.

It is an amenable number.

12188021 is a deficient number, since it is larger than the sum of its proper divisors (1).

12188021 is an equidigital number, since it uses as much as digits as its factorization.

12188021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 23.

The square root of 12188021 is about 3491.1346293147. The cubic root of 12188021 is about 230.1323812575.

The spelling of 12188021 in words is "twelve million, one hundred eighty-eight thousand, twenty-one".