21200021000221 has 16 divisors (see below), whose sum is σ = 25504278131200. Its totient is φ = 17214721555248.

The previous prime is 21200021000203. The next prime is 21200021000231. The reversal of 21200021000221 is 12200012000212.

It is a happy number.

It is not a de Polignac number, because 21200021000221 - 2³⁷ = 21062582046749 is a prime.

It is a super-2 number, since 2×21200021000221² (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 (21200021000231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5477206 + ... + 8508808.

It is an arithmetic number, because the mean of its divisors is an integer number (1594017383200).

Almost surely, 2^{21200021000221} is an apocalyptic number.

It is an amenable number.

21200021000221 is a deficient number, since it is larger than the sum of its proper divisors (4304257130979).

21200021000221 is a wasteful number, since it uses less digits than its factorization.

21200021000221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3084208.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21200021000221 its reverse (12200012000212), we get a palindrome (33400033000433).

Subtracting from 21200021000221 its reverse (12200012000212), we obtain a palindrome (9000009000009).

The spelling of 21200021000221 in words is "twenty-one trillion, two hundred billion, twenty-one million, two hundred twenty-one", and thus it is an aban number.