21111102011 has 4 divisors (see below), whose sum is σ = 21112867032. Its totient is φ = 21109336992.

The previous prime is 21111101939. The next prime is 21111102017. The reversal of 21111102011 is 11020111112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111102011 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111101983 and 21111102001.

It is not an unprimeable number, because it can be changed into a prime (21111102017) 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, 864446 + ... + 888531.

It is an arithmetic number, because the mean of its divisors is an integer number (5278216758).

Almost surely, 2^21111102011 is an apocalyptic number.

21111102011 is a deficient number, since it is larger than the sum of its proper divisors (1765021).

21111102011 is a wasteful number, since it uses less digits than its factorization.

21111102011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1765020.

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

Adding to 21111102011 its reverse (11020111112), we get a palindrome (32131213123).

The spelling of 21111102011 in words is "twenty-one billion, one hundred eleven million, one hundred two thousand, eleven".