20111611111 has 2 divisors, whose sum is σ = 20111611112. Its totient is φ = 20111611110.

The previous prime is 20111611043. The next prime is 20111611147. The reversal of 20111611111 is 11111611102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20111611111 - 2¹⁵ = 20111578343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20111611211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10055805555 + 10055805556.

It is an arithmetic number, because the mean of its divisors is an integer number (10055805556).

Almost surely, 2^20111611111 is an apocalyptic number.

20111611111 is a deficient number, since it is larger than the sum of its proper divisors (1).

20111611111 is an equidigital number, since it uses as much as digits as its factorization.

20111611111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 16.

Subtracting from 20111611111 its reverse (11111611102), we obtain a palindrome (9000000009).

The spelling of 20111611111 in words is "twenty billion, one hundred eleven million, six hundred eleven thousand, one hundred eleven".