21118110111 has 36 divisors (see below), whose sum is σ = 35495933304. Its totient is φ = 12063492000.

The previous prime is 21118110109. The next prime is 21118110113. The reversal of 21118110111 is 11101181112.

It is an interprime number because it is at equal distance from previous prime (21118110109) and next prime (21118110113).

It is not a de Polignac number, because 21118110111 - 2¹ = 21118110109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21118110113) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1780581 + ... + 1792401.

Almost surely, 2^21118110111 is an apocalyptic number.

21118110111 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21118110111 is a deficient number, since it is larger than the sum of its proper divisors (14377823193).

21118110111 is a wasteful number, since it uses less digits than its factorization.

21118110111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15892 (or 15882 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 18.

Adding to 21118110111 its reverse (11101181112), we get a palindrome (32219291223).

It can be divided in two parts, 211181101 and 11, that added together give a palindrome (211181112).

The spelling of 21118110111 in words is "twenty-one billion, one hundred eighteen million, one hundred ten thousand, one hundred eleven".