212110211221 has 4 divisors (see below), whose sum is σ = 216112290732. Its totient is φ = 208108131712.

The previous prime is 212110211123. The next prime is 212110211321. The reversal of 212110211221 is 122112011212.

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 100052648721 + 112057562500 = 316311^2 + 334750^2 .

It is a cyclic number.

It is not a de Polignac number, because 212110211221 - 2²³ = 212101822613 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212110211195 and 212110211204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212110211321) 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, 2001039676 + ... + 2001039781.

It is an arithmetic number, because the mean of its divisors is an integer number (54028072683).

Almost surely, 2^212110211221 is an apocalyptic number.

It is an amenable number.

212110211221 is a deficient number, since it is larger than the sum of its proper divisors (4002079511).

212110211221 is an equidigital number, since it uses as much as digits as its factorization.

212110211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4002079510.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 212110211221 its reverse (122112011212), we get a palindrome (334222222433).

Subtracting from 212110211221 its reverse (122112011212), we obtain a square (89998200009 = 299997²).

The spelling of 212110211221 in words is "two hundred twelve billion, one hundred ten million, two hundred eleven thousand, two hundred twenty-one".