21212210200021 has 4 divisors (see below), whose sum is σ = 21213162168192. Its totient is φ = 21211258231852.

The previous prime is 21212210200009. The next prime is 21212210200037. The reversal of 21212210200021 is 12000201221212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21212210200021 - 2¹⁷ = 21212210068949 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21212210199968 and 21212210200004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212210200061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 475950661 + ... + 475995226.

It is an arithmetic number, because the mean of its divisors is an integer number (5303290542048).

Almost surely, 2^{21212210200021} is an apocalyptic number.

It is an amenable number.

21212210200021 is a deficient number, since it is larger than the sum of its proper divisors (951968171).

21212210200021 is an equidigital number, since it uses as much as digits as its factorization.

21212210200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 951968170.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21212210200021 its reverse (12000201221212), we get a palindrome (33212411421233).

The spelling of 21212210200021 in words is "twenty-one trillion, two hundred twelve billion, two hundred ten million, two hundred thousand, twenty-one".