21200021122221 has 24 divisors (see below), whose sum is σ = 32428054825920. Its totient is φ = 13300130710656.

The previous prime is 21200021122213. The next prime is 21200021122283. The reversal of 21200021122221 is 12222112000212.

It is a happy number.

21200021122221 is a `hidden beast` number, since 212 + 0 + 0 + 0 + 211 + 22 + 221 = 666.

It is not a de Polignac number, because 21200021122221 - 2³ = 21200021122213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21200021122194 and 21200021122203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200021142221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8492545 + ... + 10701558.

It is an arithmetic number, because the mean of its divisors is an integer number (1351168951080).

Almost surely, 2^{21200021122221} is an apocalyptic number.

It is an amenable number.

21200021122221 is a deficient number, since it is larger than the sum of its proper divisors (11228033703699).

21200021122221 is a wasteful number, since it uses less digits than its factorization.

21200021122221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19201345 (or 19201342 counting only the distinct ones).

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

Adding to 21200021122221 its reverse (12222112000212), we get a palindrome (33422133122433).

The spelling of 21200021122221 in words is "twenty-one trillion, two hundred billion, twenty-one million, one hundred twenty-two thousand, two hundred twenty-one".