21111123112021 has 2 divisors, whose sum is σ = 21111123112022. Its totient is φ = 21111123112020.

The previous prime is 21111123111997. The next prime is 21111123112063. The reversal of 21111123112021 is 12021132111112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20909265202225 + 201857909796 = 4572665^2 + 449286^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111123112021 - 2⁵ = 21111123111989 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21111123112021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111123115021) 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 as a sum of consecutive naturals, namely, 10555561556010 + 10555561556011.

It is an arithmetic number, because the mean of its divisors is an integer number (10555561556011).

Almost surely, 2^{21111123112021} is an apocalyptic number.

It is an amenable number.

21111123112021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111123112021 is an equidigital number, since it uses as much as digits as its factorization.

21111123112021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 19.

Adding to 21111123112021 its reverse (12021132111112), we get a palindrome (33132255223133).

The spelling of 21111123112021 in words is "twenty-one trillion, one hundred eleven billion, one hundred twenty-three million, one hundred twelve thousand, twenty-one".