Simplify the following radical -72

According to the formula on this page, the compounded interest total must equal:
total = principal * (1 + rate/n)^n*years
where "n" is the number of compounding periods per year.  so for quarterly compounding, n = 4.
total = 5,000 * (1+(.07/4))^4*years
total = 5,000 * (1.0175)^16
total = 6599.64675604 
and rounding to nearest cent:
total = 6,599.65