You can apply for a DUNS number from Dun and Bradstreet. They are a business credit reporting agency and many business creditors pull D&B reports to review when considering an application for credit. When you apply for the DUNS number you will supply basic information about your company including its EIN.

If the EIN ever changes, you can simply update the information on your D&B report to reflect the new EIN. Since it will all be under the same DUNS number, the company's credit history will continue to be tracked. (It might not hurt to also notify existing creditors when your EIN changes, esp. those that report your payment information to D&B.) All kinds of company information can change from time to time--EIN, the company name, address, phone number--but this can be updated with D&B.