12221221 has 4 divisors (see below), whose sum is σ = 12376000. Its totient is φ = 12066444.

The previous prime is 12221207. The next prime is 12221233. The reversal of 12221221 is 12212221.

It is a happy number.

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 not a de Polignac number, because 12221221 - 2²¹ = 10124069 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 (12221021) 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, 77271 + ... + 77428.

It is an arithmetic number, because the mean of its divisors is an integer number (3094000).

Almost surely, 2^12221221 is an apocalyptic number.

It is an amenable number.

12221221 is a deficient number, since it is larger than the sum of its proper divisors (154779).

12221221 is an equidigital number, since it uses as much as digits as its factorization.

12221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154778.

The product of its digits is 32, while the sum is 13.

The square root of 12221221 is about 3495.8862967780. The cubic root of 12221221 is about 230.3411509474.

Adding to 12221221 its reverse (12212221), we get a palindrome (24433442).

It can be divided in two parts, 1 and 2221221, that added together give a palindrome (2221222).

The spelling of 12221221 in words is "twelve million, two hundred twenty-one thousand, two hundred twenty-one".