212121202221 has 8 divisors (see below), whose sum is σ = 314253632960. Its totient is φ = 141414134796.

The previous prime is 212121202193. The next prime is 212121202297. The reversal of 212121202221 is 122202121212.

It is a happy number.

212121202221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 212121202221 - 2⁶ = 212121202157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212121202194 and 212121202203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212121202621) 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 7 ways as a sum of consecutive naturals, for example, 3928170385 + ... + 3928170438.

It is an arithmetic number, because the mean of its divisors is an integer number (39281704120).

Almost surely, 2^212121202221 is an apocalyptic number.

It is an amenable number.

212121202221 is a deficient number, since it is larger than the sum of its proper divisors (102132430739).

212121202221 is an equidigital number, since it uses as much as digits as its factorization.

212121202221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7856340832 (or 7856340826 counting only the distinct ones).

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

Adding to 212121202221 its reverse (122202121212), we get a palindrome (334323323433).

The spelling of 212121202221 in words is "two hundred twelve billion, one hundred twenty-one million, two hundred two thousand, two hundred twenty-one".