212120221221 has 6 divisors (see below), whose sum is σ = 306395875110. Its totient is φ = 141413480808.

The previous prime is 212120221147. The next prime is 212120221303. The reversal of 212120221221 is 122122021212.

It is a happy number.

212120221221 is a `hidden beast` number, since 212 + 12 + 0 + 221 + 221 = 666.

212120221221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 153671840100 + 58448381121 = 392010^2 + 241761^2 .

It is not a de Polignac number, because 212120221221 - 2⁹ = 212120220709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 212120221194 and 212120221203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212120221121) 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 5 ways as a sum of consecutive naturals, for example, 11784456726 + ... + 11784456743.

It is an arithmetic number, because the mean of its divisors is an integer number (51065979185).

Almost surely, 2^212120221221 is an apocalyptic number.

It is an amenable number.

212120221221 is a deficient number, since it is larger than the sum of its proper divisors (94275653889).

212120221221 is a wasteful number, since it uses less digits than its factorization.

212120221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23568913475 (or 23568913472 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 212120221221 its reverse (122122021212), we get a palindrome (334242242433).

Subtracting from 212120221221 its reverse (122122021212), we obtain a square (89998200009 = 299997²).

The spelling of 212120221221 in words is "two hundred twelve billion, one hundred twenty million, two hundred twenty-one thousand, two hundred twenty-one".