12021221 has 4 divisors (see below), whose sum is σ = 12052992. Its totient is φ = 11989452.

The previous prime is 12021187. The next prime is 12021259. The reversal of 12021221 is 12212021.

It is a happy number.

12021221 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12021221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12020221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15311 + ... + 16076.

It is an arithmetic number, because the mean of its divisors is an integer number (3013248).

Almost surely, 2^12021221 is an apocalyptic number.

It is an amenable number.

12021221 is a deficient number, since it is larger than the sum of its proper divisors (31771).

12021221 is an equidigital number, since it uses as much as digits as its factorization.

12021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31770.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 12021221 is about 3467.1632496899. The cubic root of 12021221 is about 229.0777244859.

Adding to 12021221 its reverse (12212021), we get a palindrome (24233242).

The spelling of 12021221 in words is "twelve million, twenty-one thousand, two hundred twenty-one".