21121110211 has 2 divisors, whose sum is σ = 21121110212. Its totient is φ = 21121110210.

The previous prime is 21121110209. The next prime is 21121110223. The reversal of 21121110211 is 11201112112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21121110211 - 2¹ = 21121110209 is a prime.

It is a super-2 number, since 2×21121110211² (a number of 21 digits) contains 22 as substring.

Together with 21121110209, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21121110191 and 21121110200.

It is not a weakly prime, because it can be changed into another prime (21121110281) 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, 10560555105 + 10560555106.

It is an arithmetic number, because the mean of its divisors is an integer number (10560555106).

Almost surely, 2^21121110211 is an apocalyptic number.

21121110211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121110211 is an equidigital number, since it uses as much as digits as its factorization.

21121110211 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21121110211 its reverse (11201112112), we get a palindrome (32322222323).

The spelling of 21121110211 in words is "twenty-one billion, one hundred twenty-one million, one hundred ten thousand, two hundred eleven".