Matching principal and interest method: loan principal: 550,000 yuan, assuming annual interest rate: 4.900%, loan term: 15, monthly repayment of principal and interest: 4,320.77 yuan, total repayment: 777,738.6 yuan, * * interest payable: 227,738.6 yuan. The interest paid in 1 month is: 2245.83; The first 1 month principal repayment amount is: 2074.94.

=============

Matching principal and interest method: loan principal: 550,000 yuan, assuming annual interest rate: 4.900%, loan term: 20 years, monthly repayment of principal and interest: 3,599.44 yuan, total repayment: 863,865.6 yuan, * * interest payable: 313,865.6 yuan. The interest paid in 1 month is: 2245.83; The repayment of the principal in the 1 month is: 1353+438+0.