21212012220121 has 16 divisors (see below), whose sum is σ = 22765516611840. Its totient is φ = 19692955226880.

The previous prime is 21212012220083. The next prime is 21212012220247. The reversal of 21212012220121 is 12102221021212.

It is a cyclic number.

It is not a de Polignac number, because 21212012220121 - 2¹⁷ = 21212012089049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212012220521) 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, 6018291 + ... + 8868136.

It is an arithmetic number, because the mean of its divisors is an integer number (1422844788240).

Almost surely, 2^{21212012220121} is an apocalyptic number.

It is an amenable number.

21212012220121 is a deficient number, since it is larger than the sum of its proper divisors (1553504391719).

21212012220121 is a wasteful number, since it uses less digits than its factorization.

21212012220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14887584.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21212012220121 its reverse (12102221021212), we get a palindrome (33314233241333).

The spelling of 21212012220121 in words is "twenty-one trillion, two hundred twelve billion, twelve million, two hundred twenty thousand, one hundred twenty-one".