That is the correct answer for the PV of residual value but im not sure how to find it

Suppose the risk-free interest rate is 5.6% APR with monthly compounding. If a $2.2 million MRI machine can be leased for 4 years for $39,000 per month, what residual value must the lessor recover to break even in a perfect market with no risk? (Assume that the first payment is made immediately, so the payments occur at the beginning of each month.) The present value of the residual value is $ 518,519'. (Round to the nearest dollar.) The residual value must be $ (Round to the nearest dollar.)