You need a 30-year, fixed-rate mortgage to buy a new home for $500,000. You will pay 20 percent down and borrow the rest at an APR of 6 percent compounded monthly. However, you can only make monthly payments of $1,800. The lender offers that you pay off the remaining loan balance at the end of 30 years as a single balloon payment. What will be the amount of the balloon payment if you are to keep your monthly payments at $1,800?