This number is a composite.
Just showing those entries submitted by 'Post': (Click here to show all)
18158961567721 = 13 * 373 * 11173 * 335173 is a Zeisel Number because its four prime factors are consecutive elements of the linear recurrence prime(i+1) = 30*prime(i) - 17. Curiously, it is also an emirp, since 12776516985181 is prime. The digital sum 67 is prime. [Post]