21202011111121 has 2 divisors, whose sum is σ = 21202011111122. Its totient is φ = 21202011111120.

The previous prime is 21202011111119. The next prime is 21202011111137. The reversal of 21202011111121 is 12111111020212.

It is an a-pointer prime, because the next prime (21202011111137) can be obtained adding 21202011111121 to its sum of digits (16).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20702500000000 + 499511111121 = 4550000^2 + 706761^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202011111121 - 2¹ = 21202011111119 is a prime.

Together with 21202011111119, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21202011111095 and 21202011111104.

It is not a weakly prime, because it can be changed into another prime (21202011111181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601005555560 + 10601005555561.

It is an arithmetic number, because the mean of its divisors is an integer number (10601005555561).

Almost surely, 2^{21202011111121} is an apocalyptic number.

It is an amenable number.

21202011111121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202011111121 is an equidigital number, since it uses as much as digits as its factorization.

21202011111121 is an evil number, because the sum of its binary digits is even.

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

Adding to 21202011111121 its reverse (12111111020212), we get a palindrome (33313122131333).

Subtracting from 21202011111121 its reverse (12111111020212), we obtain a palindrome (9090900090909).

The spelling of 21202011111121 in words is "twenty-one trillion, two hundred two billion, eleven million, one hundred eleven thousand, one hundred twenty-one".