21102110111 has 4 divisors (see below), whose sum is σ = 21145088424. Its totient is φ = 21059131800.

The previous prime is 21102110039. The next prime is 21102110123. The reversal of 21102110111 is 11101120112.

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 21102110111 - 2¹⁸ = 21101847967 is a prime.

It is a super-2 number, since 2×21102110111² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21102110092 and 21102110101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102110171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21488420 + ... + 21489401.

It is an arithmetic number, because the mean of its divisors is an integer number (5286272106).

Almost surely, 2^21102110111 is an apocalyptic number.

21102110111 is a deficient number, since it is larger than the sum of its proper divisors (42978313).

21102110111 is an equidigital number, since it uses as much as digits as its factorization.

21102110111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42978312.

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

Adding to 21102110111 its reverse (11101120112), we get a palindrome (32203230223).

The spelling of 21102110111 in words is "twenty-one billion, one hundred two million, one hundred ten thousand, one hundred eleven".