20111121191 has 16 divisors (see below), whose sum is σ = 23760770880. Its totient is φ = 16663345920.

The previous prime is 20111121187. The next prime is 20111121209. The reversal of 20111121191 is 19112111102.

It is a cyclic number.

It is not a de Polignac number, because 20111121191 - 2² = 20111121187 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20111121181) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 290156 + ... + 352721.

It is an arithmetic number, because the mean of its divisors is an integer number (1485048180).

Almost surely, 2^20111121191 is an apocalyptic number.

20111121191 is a deficient number, since it is larger than the sum of its proper divisors (3649649689).

20111121191 is a wasteful number, since it uses less digits than its factorization.

20111121191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643034.

The product of its (nonzero) digits is 36, while the sum is 20.

Adding to 20111121191 its reverse (19112111102), we get a palindrome (39223232293).

The spelling of 20111121191 in words is "twenty billion, one hundred eleven million, one hundred twenty-one thousand, one hundred ninety-one".