21111010211 has 4 divisors (see below), whose sum is σ = 21119725392. Its totient is φ = 21102295032.

The previous prime is 21111010171. The next prime is 21111010223. The reversal of 21111010211 is 11201011112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21111010211 - 2²² = 21106815907 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111010192 and 21111010201.

It is not an unprimeable number, because it can be changed into a prime (21111010241) 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 in 3 ways as a sum of consecutive naturals, for example, 4353956 + ... + 4358801.

It is an arithmetic number, because the mean of its divisors is an integer number (5279931348).

Almost surely, 2^21111010211 is an apocalyptic number.

21111010211 is a deficient number, since it is larger than the sum of its proper divisors (8715181).

21111010211 is an equidigital number, since it uses as much as digits as its factorization.

21111010211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8715180.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21111010211 its reverse (11201011112), we get a palindrome (32312021323).

Subtracting from 21111010211 its reverse (11201011112), we obtain a palindrome (9909999099).

The spelling of 21111010211 in words is "twenty-one billion, one hundred eleven million, ten thousand, two hundred eleven".