The annual interest rate is 5.5%, the monthly interest rate is 5.5%/ 1.24 million, and it is 30 years (360 months), and it is calculated according to the repayment method of equal principal and interest (same monthly repayment amount):

Monthly repayment amount = 400,000 * 5.5%/12 * (1+5.5%/12) 360/((1+5.5%12) 360.

Total interest = 2271.16 * 360-400000 = 417617.60.

Description: 360 is the power of 360.