Well, I think you can avail three very valuable set of problems.
1. Gmat club forum- Number Properties- You can find a lot of questions on this forum, search using the tag function and you will find a number of questions with 6000-700 & 700 above range.
2. GMAT Club Test: Topic "number properties". (you will have to buy them).
3. Jeff Sackmann Question Sets: You can purchase those with the bifurcation of advanced problems & foundation stage. This is a good resource too.
Best of luck!!
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