212112111221 has 16 divisors (see below), whose sum is σ = 229839192576. Its totient is φ = 194985812736.

The previous prime is 212112111209. The next prime is 212112111227. The reversal of 212112111221 is 122111211212.

It is a cyclic number.

It is not a de Polignac number, because 212112111221 - 2¹⁸ = 212111849077 is a prime.

It is a super-2 number, since 2×212112111221² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

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 212112111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212112111227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 116555 + ... + 661671.

It is an arithmetic number, because the mean of its divisors is an integer number (14364949536).

Almost surely, 2^212112111221 is an apocalyptic number.

It is an amenable number.

212112111221 is a deficient number, since it is larger than the sum of its proper divisors (17727081355).

212112111221 is a wasteful number, since it uses less digits than its factorization.

212112111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 545668.

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

Adding to 212112111221 its reverse (122111211212), we get a palindrome (334223322433).

Subtracting from 212112111221 its reverse (122111211212), we obtain a palindrome (90000900009).

The spelling of 212112111221 in words is "two hundred twelve billion, one hundred twelve million, one hundred eleven thousand, two hundred twenty-one".