I might start by:
1. Save a copy of the original file.
2. Name it [filename] first page.pdf
3. Delete everything but the first page of the PDF. That means 12,696 pages have to go.
4. Try exporting that single page to Excel and see how it goes.
If it works, create another copy of the original PDF, delete all but pages 2-6, name it [filename] 2-6.pdf. Then try to export that and see what happens. If that works, take a copy of the original file and export the next 10 pages. Then 20, then 40, adding pages until you find the threshold where it doesn't work anymore. Back off incrementally from that point, then continue.
NOTE: Be sure to always work from a copy of the original file. If things go bad, your original file will be a safe fallback as long as you always work from a copy of the original file.
Right now we don't know if the system is choking from the process or because it's overdosing on processing your massive PDF file. The tests above will help us determine if it's one or the other, and give us insight on what we need to do from there. Let us know how the test above works out, and we'll do our best to help.
Hope this helps,
Randy