21200201202121 has 4 divisors (see below), whose sum is σ = 21438405710100. Its totient is φ = 20961996694144.

The previous prime is 21200201202113. The next prime is 21200201202139. The reversal of 21200201202121 is 12120210200212.

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 13239118873600 + 7961082328521 = 3638560^2 + 2821539^2 .

It is a cyclic number.

It is not a de Polignac number, because 21200201202121 - 2³ = 21200201202113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21200201202095 and 21200201202104.

It is not an unprimeable number, because it can be changed into a prime (21200201202161) 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, 119102253856 + ... + 119102254033.

It is an arithmetic number, because the mean of its divisors is an integer number (5359601427525).

Almost surely, 2^{21200201202121} is an apocalyptic number.

It is an amenable number.

21200201202121 is a deficient number, since it is larger than the sum of its proper divisors (238204507979).

21200201202121 is an equidigital number, since it uses as much as digits as its factorization.

21200201202121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238204507978.

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

Adding to 21200201202121 its reverse (12120210200212), we get a palindrome (33320411402333).

The spelling of 21200201202121 in words is "twenty-one trillion, two hundred billion, two hundred one million, two hundred two thousand, one hundred twenty-one".