21100111211 has 16 divisors (see below), whose sum is σ = 22574476800. Its totient is φ = 19662987168.

The previous prime is 21100111199. The next prime is 21100111261. The reversal of 21100111211 is 11211100112.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21100111211 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100111192 and 21100111201.

It is not an unprimeable number, because it can be changed into a prime (21100111261) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 903761 + ... + 926813.

It is an arithmetic number, because the mean of its divisors is an integer number (1410904800).

Almost surely, 2^21100111211 is an apocalyptic number.

21100111211 is a deficient number, since it is larger than the sum of its proper divisors (1474365589).

21100111211 is a wasteful number, since it uses less digits than its factorization.

21100111211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23858.

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

Adding to 21100111211 its reverse (11211100112), we get a palindrome (32311211323).

The spelling of 21100111211 in words is "twenty-one billion, one hundred million, one hundred eleven thousand, two hundred eleven".