21022100200021 has 16 divisors (see below), whose sum is σ = 22402748787120. Its totient is φ = 19657853501440.

The previous prime is 21022100199977. The next prime is 21022100200033. The reversal of 21022100200021 is 12000200122012.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 126139335921 + 20895960864100 = 355161^2 + 4571210^2 .

It is a cyclic number.

It is not a de Polignac number, because 21022100200021 - 2¹⁵ = 21022100167253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21022100199974 and 21022100200010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022100200091) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4485100 + ... + 7884181.

It is an arithmetic number, because the mean of its divisors is an integer number (1400171799195).

Almost surely, 2^{21022100200021} is an apocalyptic number.

It is an amenable number.

21022100200021 is a deficient number, since it is larger than the sum of its proper divisors (1380648587099).

21022100200021 is a wasteful number, since it uses less digits than its factorization.

21022100200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12369944.

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

Adding to 21022100200021 its reverse (12000200122012), we get a palindrome (33022300322033).

The spelling of 21022100200021 in words is "twenty-one trillion, twenty-two billion, one hundred million, two hundred thousand, twenty-one".