21010111111 has 16 divisors (see below), whose sum is σ = 23305651200. Its totient is φ = 18779090400.

The previous prime is 21010111103. The next prime is 21010111163. The reversal of 21010111111 is 11111101012.

It is a cyclic number.

It is not a de Polignac number, because 21010111111 - 2³ = 21010111103 is a prime.

It is a Duffinian number.

21010111111 is a modest number, since divided by 111111 gives 21010 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21013111111) 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 15 ways as a sum of consecutive naturals, for example, 2087830 + ... + 2097868.

It is an arithmetic number, because the mean of its divisors is an integer number (1456603200).

Almost surely, 2^21010111111 is an apocalyptic number.

21010111111 is a deficient number, since it is larger than the sum of its proper divisors (2295540089).

21010111111 is a wasteful number, since it uses less digits than its factorization.

21010111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13230.

The product of its (nonzero) digits is 2, while the sum is 10.

Adding to 21010111111 its reverse (11111101012), we get a palindrome (32121212123).

The spelling of 21010111111 in words is "twenty-one billion, ten million, one hundred eleven thousand, one hundred eleven".