21102111111 has 8 divisors (see below), whose sum is σ = 28338567040. Its totient is φ = 13966864632.

The previous prime is 21102111103. The next prime is 21102111119. The reversal of 21102111111 is 11111120112.

It is an interprime number because it is at equal distance from previous prime (21102111103) and next prime (21102111119).

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

It is not a de Polignac number, because 21102111111 - 2³ = 21102111103 is a prime.

It is a Duffinian number.

21102111111 is a modest number, since divided by 111111 gives 21102 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102111119) 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 7 ways as a sum of consecutive naturals, for example, 25301875 + ... + 25302708.

It is an arithmetic number, because the mean of its divisors is an integer number (3542320880).

Almost surely, 2^21102111111 is an apocalyptic number.

21102111111 is a deficient number, since it is larger than the sum of its proper divisors (7236455929).

21102111111 is a wasteful number, since it uses less digits than its factorization.

21102111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50604725.

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

Adding to 21102111111 its reverse (11111120112), we get a palindrome (32213231223).

Subtracting from 21102111111 its reverse (11111120112), we obtain a palindrome (9990990999).

The spelling of 21102111111 in words is "twenty-one billion, one hundred two million, one hundred eleven thousand, one hundred eleven".