PMT can have at least 2 meanings:
1 - What is the "Loan Payment"
2- What is the PMT to save a certain sum in the future.
I assume that you are looking for a loan payment. If so, then you have to use this formula to calculate it: PMT=PV. R.{[1 + R]^N/ [1 + R]^N - 1}, Where R=Interest rate per period, N=number of periods, P=periodic payment, PV=Present value.
PMT = 21,298 x 0.013{[1 +0.013]^83 / [1 + 0.013]^83 - 1}
PMT =276.874 x {[2.921353... / 1.921353..... }
PMT =276.874 x 1.5204667....
PMT =$420.98 - The loan payment??.