21002200021121 has 6 divisors (see below), whose sum is σ = 23085062833266. Its totient is φ = 19092909110000.

The previous prime is 21002200021111. The next prime is 21002200021133. The reversal of 21002200021121 is 12112000220012.

It can be written as a sum of positive squares in only one way, i.e., 20298052472896 + 704147548225 = 4505336^2 + 839135^2 .

It is not a de Polignac number, because 21002200021121 - 2⁶ = 21002200021057 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002200021096 and 21002200021105.

It is not an unprimeable number, because it can be changed into a prime (21002200021111) 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 5 ways as a sum of consecutive naturals, for example, 86785950380 + ... + 86785950621.

It is an arithmetic number, because the mean of its divisors is an integer number (3847510472211).

Almost surely, 2^{21002200021121} is an apocalyptic number.

It is an amenable number.

21002200021121 is a deficient number, since it is larger than the sum of its proper divisors (2082862812145).

21002200021121 is a wasteful number, since it uses less digits than its factorization.

21002200021121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173571901023 (or 173571901012 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21002200021121 its reverse (12112000220012), we get a palindrome (33114200241133).

The spelling of 21002200021121 in words is "twenty-one trillion, two billion, two hundred million, twenty-one thousand, one hundred twenty-one".