20111120191 has 4 divisors (see below), whose sum is σ = 20411286232. Its totient is φ = 19810954152.

The previous prime is 20111120177. The next prime is 20111120231. The reversal of 20111120191 is 19102111102.

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-20111120191 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 (20111120111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 150082920 + ... + 150083053.

It is an arithmetic number, because the mean of its divisors is an integer number (5102821558).

Almost surely, 2^20111120191 is an apocalyptic number.

20111120191 is a deficient number, since it is larger than the sum of its proper divisors (300166041).

20111120191 is an equidigital number, since it uses as much as digits as its factorization.

20111120191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300166040.

The product of its (nonzero) digits is 36, while the sum is 19.

Adding to 20111120191 its reverse (19102111102), we get a palindrome (39213231293).

The spelling of 20111120191 in words is "twenty billion, one hundred eleven million, one hundred twenty thousand, one hundred ninety-one".