18205985191 has 2 divisors, whose sum is σ = 18205985192. Its totient is φ = 18205985190.

The previous prime is 18205985143. The next prime is 18205985201. The reversal of 18205985191 is 19158950281.

It is a strong prime.

It is an emirp because it is prime and its reverse (19158950281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18205985191 - 2¹¹ = 18205983143 is a prime.

It is a super-2 number, since 2×18205985191² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18205985131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9102992595 + 9102992596.

It is an arithmetic number, because the mean of its divisors is an integer number (9102992596).

Almost surely, 2^18205985191 is an apocalyptic number.

18205985191 is a deficient number, since it is larger than the sum of its proper divisors (1).

18205985191 is an equidigital number, since it uses as much as digits as its factorization.

18205985191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 259200, while the sum is 49.

The spelling of 18205985191 in words is "eighteen billion, two hundred five million, nine hundred eighty-five thousand, one hundred ninety-one".