212121101221 has 4 divisors (see below), whose sum is σ = 212128181100. Its totient is φ = 212114021344.

The previous prime is 212121101219. The next prime is 212121101233. The reversal of 212121101221 is 122101121212.

212121101221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 134330313121 + 77790788100 = 366511^2 + 278910^2 .

It is a cyclic number.

It is not a de Polignac number, because 212121101221 - 2¹ = 212121101219 is a prime.

It is a super-3 number, since 3×212121101221³ (a number of 35 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212121101195 and 212121101204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212121171221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3494806 + ... + 3554983.

It is an arithmetic number, because the mean of its divisors is an integer number (53032045275).

Almost surely, 2^212121101221 is an apocalyptic number.

It is an amenable number.

212121101221 is a deficient number, since it is larger than the sum of its proper divisors (7079879).

212121101221 is an equidigital number, since it uses as much as digits as its factorization.

212121101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7079878.

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

Adding to 212121101221 its reverse (122101121212), we get a palindrome (334222222433).

The spelling of 212121101221 in words is "two hundred twelve billion, one hundred twenty-one million, one hundred one thousand, two hundred twenty-one".