21200020332221 has 4 divisors (see below), whose sum is σ = 21253420887612. Its totient is φ = 21146619776832.

The previous prime is 21200020332217. The next prime is 21200020332223. The reversal of 21200020332221 is 12223302000212.

It is a happy number.

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 11081482000996 + 10118538331225 = 3328886^2 + 3180965^2 .

It is a cyclic number.

It is not a de Polignac number, because 21200020332221 - 2² = 21200020332217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21200020332193 and 21200020332202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200020332223) 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, 26700277100 + ... + 26700277893.

It is an arithmetic number, because the mean of its divisors is an integer number (5313355221903).

Almost surely, 2^{21200020332221} is an apocalyptic number.

It is an amenable number.

21200020332221 is a deficient number, since it is larger than the sum of its proper divisors (53400555391).

21200020332221 is an equidigital number, since it uses as much as digits as its factorization.

21200020332221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53400555390.

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21200020332221 its reverse (12223302000212), we get a palindrome (33423322332433).

The spelling of 21200020332221 in words is "twenty-one trillion, two hundred billion, twenty million, three hundred thirty-two thousand, two hundred twenty-one".