212211111221 has 4 divisors (see below), whose sum is σ = 212217457452. Its totient is φ = 212204764992.

The previous prime is 212211111193. The next prime is 212211111251. The reversal of 212211111221 is 122111112212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9877576996 + 202333534225 = 99386^2 + 449815^2 .

It is a cyclic number.

It is not a de Polignac number, because 212211111221 - 2¹⁰ = 212211110197 is a prime.

It is a super-2 number, since 2×212211111221² (a number of 23 digits) contains 22 as substring.

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 212211111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212211111251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3122690 + ... + 3189923.

It is an arithmetic number, because the mean of its divisors is an integer number (53054364363).

Almost surely, 2^212211111221 is an apocalyptic number.

It is an amenable number.

212211111221 is a deficient number, since it is larger than the sum of its proper divisors (6346231).

212211111221 is an equidigital number, since it uses as much as digits as its factorization.

212211111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6346230.

The product of its digits is 32, while the sum is 17.

Adding to 212211111221 its reverse (122111112212), we get a palindrome (334322223433).

Subtracting from 212211111221 its reverse (122111112212), we obtain a palindrome (90099999009).

It can be divided in two parts, 2 and 12211111221, that multiplied together give a palindrome (24422222442).

The spelling of 212211111221 in words is "two hundred twelve billion, two hundred eleven million, one hundred eleven thousand, two hundred twenty-one".