21120102121 has 2 divisors, whose sum is σ = 21120102122. Its totient is φ = 21120102120.

The previous prime is 21120102119. The next prime is 21120102139. The reversal of 21120102121 is 12120102112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21119355625 + 746496 = 145325^2 + 864^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120102121 - 2¹ = 21120102119 is a prime.

Together with 21120102119, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21120102161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560051060 + 10560051061.

It is an arithmetic number, because the mean of its divisors is an integer number (10560051061).

Almost surely, 2^21120102121 is an apocalyptic number.

It is an amenable number.

21120102121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120102121 is an equidigital number, since it uses as much as digits as its factorization.

21120102121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21120102121 its reverse (12120102112), we get a palindrome (33240204233).

Subtracting from 21120102121 its reverse (12120102112), we obtain a palindrome (9000000009).

The spelling of 21120102121 in words is "twenty-one billion, one hundred twenty million, one hundred two thousand, one hundred twenty-one".