21212020222221 has 64 divisors (see below), whose sum is σ = 30243061094400. Its totient is φ = 13186549426176.

The previous prime is 21212020222187. The next prime is 21212020222273. The reversal of 21212020222221 is 12222202021212.

It is not a de Polignac number, because 21212020222221 - 2⁷ = 21212020222093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212020222621) 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 63 ways as a sum of consecutive naturals, for example, 1214396730 + ... + 1214414196.

It is an arithmetic number, because the mean of its divisors is an integer number (472547829600).

Almost surely, 2^{21212020222221} is an apocalyptic number.

It is an amenable number.

21212020222221 is a deficient number, since it is larger than the sum of its proper divisors (9031040872179).

21212020222221 is a wasteful number, since it uses less digits than its factorization.

21212020222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18898.

The product of its (nonzero) digits is 512, while the sum is 21.

Adding to 21212020222221 its reverse (12222202021212), we get a palindrome (33434222243433).

The spelling of 21212020222221 in words is "twenty-one trillion, two hundred twelve billion, twenty million, two hundred twenty-two thousand, two hundred twenty-one".