12018221 has 4 divisors (see below), whose sum is σ = 12027132. Its totient is φ = 12009312.

The previous prime is 12018217. The next prime is 12018247. The reversal of 12018221 is 12281021.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 6325225 + 5692996 = 2515^2 + 2386^2 .

It is a cyclic number.

It is not a de Polignac number, because 12018221 - 2² = 12018217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12018221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12018211) 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 in 3 ways as a sum of consecutive naturals, for example, 1970 + ... + 5283.

It is an arithmetic number, because the mean of its divisors is an integer number (3006783).

Almost surely, 2^12018221 is an apocalyptic number.

It is an amenable number.

12018221 is a deficient number, since it is larger than the sum of its proper divisors (8911).

12018221 is an equidigital number, since it uses as much as digits as its factorization.

12018221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8910.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 12018221 is about 3466.7305923593. The cubic root of 12018221 is about 229.0586667893.

Adding to 12018221 its reverse (12281021), we get a palindrome (24299242).

The spelling of 12018221 in words is "twelve million, eighteen thousand, two hundred twenty-one".