21110211111 has 8 divisors (see below), whose sum is σ = 30705761664. Its totient is φ = 12794067320.

The previous prime is 21110211103. The next prime is 21110211121. The reversal of 21110211111 is 11111201112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21110211111 - 2³ = 21110211103 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110211121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 319851651 + ... + 319851716.

It is an arithmetic number, because the mean of its divisors is an integer number (3838220208).

Almost surely, 2^21110211111 is an apocalyptic number.

21110211111 is a deficient number, since it is larger than the sum of its proper divisors (9595550553).

21110211111 is a wasteful number, since it uses less digits than its factorization.

21110211111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639703381.

The product of its (nonzero) digits is 4, while the sum is 12.

Adding to 21110211111 its reverse (11111201112), we get a palindrome (32221412223).

Subtracting from 21110211111 its reverse (11111201112), we obtain a palindrome (9999009999).

It can be divided in two parts, 21110 and 211111, that added together give a triangular number (232221 = T₆₈₁).

The spelling of 21110211111 in words is "twenty-one billion, one hundred ten million, two hundred eleven thousand, one hundred eleven".