21100223210221 has 4 divisors (see below), whose sum is σ = 21216799029244. Its totient is φ = 20983647391200.

The previous prime is 21100223210173. The next prime is 21100223210267. The reversal of 21100223210221 is 12201232200112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4745923248196 + 16354299962025 = 2178514^2 + 4044045^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100223210221 - 2²⁹ = 21099686339309 is a prime.

It is a super-2 number, since 2×21100223210221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100223210821) 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 3 ways as a sum of consecutive naturals, for example, 58287909240 + ... + 58287909601.

It is an arithmetic number, because the mean of its divisors is an integer number (5304199757311).

Almost surely, 2^{21100223210221} is an apocalyptic number.

It is an amenable number.

21100223210221 is a deficient number, since it is larger than the sum of its proper divisors (116575819023).

21100223210221 is a wasteful number, since it uses less digits than its factorization.

21100223210221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116575819022.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21100223210221 its reverse (12201232200112), we get a palindrome (33301455410333).

The spelling of 21100223210221 in words is "twenty-one trillion, one hundred billion, two hundred twenty-three million, two hundred ten thousand, two hundred twenty-one".