21120211120121 has 2 divisors, whose sum is σ = 21120211120122. Its totient is φ = 21120211120120.

The previous prime is 21120211120111. The next prime is 21120211120139. The reversal of 21120211120121 is 12102111202112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15991961010025 + 5128250110096 = 3998995^2 + 2264564^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21120211120121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21120211120121.

It is not a weakly prime, because it can be changed into another prime (21120211120111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560105560060 + 10560105560061.

It is an arithmetic number, because the mean of its divisors is an integer number (10560105560061).

Almost surely, 2^{21120211120121} is an apocalyptic number.

It is an amenable number.

21120211120121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120211120121 is an equidigital number, since it uses as much as digits as its factorization.

21120211120121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21120211120121 its reverse (12102111202112), we get a palindrome (33222322322233).

The spelling of 21120211120121 in words is "twenty-one trillion, one hundred twenty billion, two hundred eleven million, one hundred twenty thousand, one hundred twenty-one".