18159921191 has 4 divisors (see below), whose sum is σ = 18786125400. Its totient is φ = 17533716984.

The previous prime is 18159921167. The next prime is 18159921209. The reversal of 18159921191 is 19112995181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19112995181 = 7 ⋅2730427883.

It is a cyclic number.

It is not a de Polignac number, because 18159921191 - 2¹⁸ = 18159659047 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 (18159921151) 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, 313102061 + ... + 313102118.

It is an arithmetic number, because the mean of its divisors is an integer number (4696531350).

Almost surely, 2^18159921191 is an apocalyptic number.

18159921191 is a deficient number, since it is larger than the sum of its proper divisors (626204209).

18159921191 is an equidigital number, since it uses as much as digits as its factorization.

18159921191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 626204208.

The product of its digits is 58320, while the sum is 47.

The spelling of 18159921191 in words is "eighteen billion, one hundred fifty-nine million, nine hundred twenty-one thousand, one hundred ninety-one".