21212222200021 has 16 divisors (see below), whose sum is σ = 21517773653376. Its totient is φ = 20908584999936.

The previous prime is 21212222200019. The next prime is 21212222200031. The reversal of 21212222200021 is 12000222221212.

It is a cyclic number.

It is not a de Polignac number, because 21212222200021 - 2¹ = 21212222200019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212222200031) 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, 28478080 + ... + 29213446.

It is an arithmetic number, because the mean of its divisors is an integer number (1344860853336).

Almost surely, 2^{21212222200021} is an apocalyptic number.

It is an amenable number.

21212222200021 is a deficient number, since it is larger than the sum of its proper divisors (305551453355).

21212222200021 is an equidigital number, since it uses as much as digits as its factorization.

21212222200021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 736668.

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21212222200021 its reverse (12000222221212), we get a palindrome (33212444421233).

The spelling of 21212222200021 in words is "twenty-one trillion, two hundred twelve billion, two hundred twenty-two million, two hundred thousand, twenty-one".