21112111211 has 2 divisors, whose sum is σ = 21112111212. Its totient is φ = 21112111210.

The previous prime is 21112111201. The next prime is 21112111243. The reversal of 21112111211 is 11211121112.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112111211 is a prime.

It is not a weakly prime, because it can be changed into another prime (21112111201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556055605 + 10556055606.

It is an arithmetic number, because the mean of its divisors is an integer number (10556055606).

Almost surely, 2^21112111211 is an apocalyptic number.

21112111211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112111211 is an equidigital number, since it uses as much as digits as its factorization.

21112111211 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8, while the sum is 14.

Adding to 21112111211 its reverse (11211121112), we get a palindrome (32323232323).

Subtracting from 21112111211 its reverse (11211121112), we obtain a palindrome (9900990099).

It can be divided in two parts, 211121112 and 11, that multiplied together give a palindrome (2322332232).

The spelling of 21112111211 in words is "twenty-one billion, one hundred twelve million, one hundred eleven thousand, two hundred eleven".