20111011111 has 4 divisors (see below), whose sum is σ = 21169485400. Its totient is φ = 19052536824.

The previous prime is 20111011093. The next prime is 20111011153. The reversal of 20111011111 is 11111011102.

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

It is not a de Polignac number, because 20111011111 - 2⁵ = 20111011079 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20111611111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 529237116 + ... + 529237153.

It is an arithmetic number, because the mean of its divisors is an integer number (5292371350).

Almost surely, 2^20111011111 is an apocalyptic number.

20111011111 is a deficient number, since it is larger than the sum of its proper divisors (1058474289).

20111011111 is a wasteful number, since it uses less digits than its factorization.

20111011111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1058474288.

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

Adding to 20111011111 its reverse (11111011102), we get a palindrome (31222022213).

Subtracting from 20111011111 its reverse (11111011102), we obtain a palindrome (9000000009).

The spelling of 20111011111 in words is "twenty billion, one hundred eleven million, eleven thousand, one hundred eleven".