21101020021121 has 2 divisors, whose sum is σ = 21101020021122. Its totient is φ = 21101020021120.

The previous prime is 21101020021097. The next prime is 21101020021157. The reversal of 21101020021121 is 12112002010112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10560478596721 + 10540541424400 = 3249689^2 + 3246620^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21101020021121 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21101020021096 and 21101020021105.

It is not a weakly prime, because it can be changed into another prime (21101020021181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550510010560 + 10550510010561.

It is an arithmetic number, because the mean of its divisors is an integer number (10550510010561).

Almost surely, 2^{21101020021121} is an apocalyptic number.

It is an amenable number.

21101020021121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101020021121 is an equidigital number, since it uses as much as digits as its factorization.

21101020021121 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 14.

Adding to 21101020021121 its reverse (12112002010112), we get a palindrome (33213022031233).

The spelling of 21101020021121 in words is "twenty-one trillion, one hundred one billion, twenty million, twenty-one thousand, one hundred twenty-one".