Start by calling your bank and asking them how (or if) they will honor the check. (I think my bank gives the numerals priority over the written amount.)
If it is not cashed yet, you could also stop payment to ensure that neither amount gets paid. Then, go to the IRS payments web site and make a direct payment of the correct amount. (The IRS may send you a bill for late payment interest but it won't be too much if you catch it soon.) https://www.irs.gov/Payments
