How to pass this test? I got WA for several times.

I had WA @ #85 for many times, too.

Try this testcase:
k = 144

The correct answer is n = 185, rather than n = 169.
The same factor, 13, could NOT be used twice in different layers of search.

Good luck.

if k = 144 my program gives n = 185, but I got WA 85, Why ?

if k = 144 my program gives n = 185, but I got WA 85, Why ?