21123203110211 has 2 divisors, whose sum is σ = 21123203110212. Its totient is φ = 21123203110210.

The previous prime is 21123203110171. The next prime is 21123203110213. The reversal of 21123203110211 is 11201130232112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21123203110211 is a prime.

Together with 21123203110213, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21123203110213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561601555105 + 10561601555106.

It is an arithmetic number, because the mean of its divisors is an integer number (10561601555106).

Almost surely, 2^{21123203110211} is an apocalyptic number.

21123203110211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123203110211 is an equidigital number, since it uses as much as digits as its factorization.

21123203110211 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 20.

Adding to 21123203110211 its reverse (11201130232112), we get a palindrome (32324333342323).

The spelling of 21123203110211 in words is "twenty-one trillion, one hundred twenty-three billion, two hundred three million, one hundred ten thousand, two hundred eleven".