Assuming the periodic deposit is made daily into the annuity at 4.7% compounded daily, the future value of the annuity will be $16,011,688.49 at the end of 18 years.
The future value can be computed using an online finance calculator. In this situation, it is assumed that the periodic deposit is daily since this was not specified.
N (# of periods) = 6,570 (18 years x 365 days)
I/Y (Interest per year) = 4.7%
PV (Present Value) = $0
PMT (Periodic Payment) = $1,550
Results
FV = $16,011,688.49
The sum of all periodic payments = $10,183,500.00
Total Interest $5,828,188.49