None of the major markets accept 510(k) for "fast-track" registration, but you can certainly leverage the documentation created for the submission.
Virtually all countries have separate requirement for conformity assessment (similar to 510(k)) and QMS requirements (e.g., ISO13485 or MDSAP cert, which FDA does not require or even audit to QSR).
The easiest place may be Australia, UK, Canada and maybe Brazil, depending on classification, especially if you can squeeze in as Class I device.
Canada requires MDSAP cert for Class II and higher and other counties expect it.
And I second ChrisM's sentiment. You sales and the management team should figure out where they can sell first. Marketing your product in another country is not as simple as just getting clearance and making a statement on your website that it's available there.