21021122222121 has 12 divisors (see below), whose sum is σ = 32604189569232. Its totient is φ = 12012069841128.

The previous prime is 21021122222041. The next prime is 21021122222171. The reversal of 21021122222121 is 12122222112012.

It is not a de Polignac number, because 21021122222121 - 2³³ = 21012532287529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21021122222171) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 71500415575 + ... + 71500415868.

It is an arithmetic number, because the mean of its divisors is an integer number (2717015797436).

Almost surely, 2^{21021122222121} is an apocalyptic number.

21021122222121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21021122222121 is a deficient number, since it is larger than the sum of its proper divisors (11583067347111).

21021122222121 is a wasteful number, since it uses less digits than its factorization.

21021122222121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143000831460 (or 143000831453 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 21.

Adding to 21021122222121 its reverse (12122222112012), we get a palindrome (33143344334133).

The spelling of 21021122222121 in words is "twenty-one trillion, twenty-one billion, one hundred twenty-two million, two hundred twenty-two thousand, one hundred twenty-one".