21111211122011 has 2 divisors, whose sum is σ = 21111211122012. Its totient is φ = 21111211122010.

The previous prime is 21111211121989. The next prime is 21111211122151. The reversal of 21111211122011 is 11022111211112.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111211122011 is a prime.

It is not a weakly prime, because it can be changed into another prime (21111211122311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555605561005 + 10555605561006.

It is an arithmetic number, because the mean of its divisors is an integer number (10555605561006).

Almost surely, 2^{21111211122011} is an apocalyptic number.

21111211122011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111211122011 is an equidigital number, since it uses as much as digits as its factorization.

21111211122011 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 17.

Adding to 21111211122011 its reverse (11022111211112), we get a palindrome (32133322333123).

The spelling of 21111211122011 in words is "twenty-one trillion, one hundred eleven billion, two hundred eleven million, one hundred twenty-two thousand, eleven".