12211221 has 32 divisors (see below), whose sum is σ = 18626688. Its totient is φ = 7050240.

The previous prime is 12211217. The next prime is 12211223.

12211221 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 12211221 - 2² = 12211217 is a prime.

It is a super-2 number, since 2×12211221² = 298227836621682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 12211197 and 12211206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12211223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 89065 + ... + 89201.

It is an arithmetic number, because the mean of its divisors is an integer number (582084).

Almost surely, 2^12211221 is an apocalyptic number.

12211221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12211221 is a deficient number, since it is larger than the sum of its proper divisors (6415467).

12211221 is a wasteful number, since it uses less digits than its factorization.

12211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261.

The product of its digits is 16, while the sum is 12.

The square root of 12211221 is about 3494.4557516157. The cubic root of 12211221 is about 230.2783083436.

It can be divided in two parts, 1221 and 1221, that added together give a palindrome (2442).

The spelling of 12211221 in words is "twelve million, two hundred eleven thousand, two hundred twenty-one".