The monthly interest of 2.8 million depends on the interest rate.

The monthly interest of 2.8 million is calculated based on the interest rate. Interest rate refers to the proportional relationship between the interest generated by borrowing funds and the principal. Assuming the interest rate is 1%, the monthly interest of 2.8 million is 2.8 million × 1% = 28,000 yuan. If the interest rate is 2%, the monthly interest of 2.8 million is 2.8 million × 2% = 56,000 yuan. The higher the interest rate, the more interest is generated; the lower the interest rate, the less interest is generated. Please note that this is just an example and actual rates may vary based on specific circumstances. In practice, interest rates are usually set by financial institutions or governments and are adjusted based on market conditions and the borrower's credit profile.