Compliance requirements: (1) Bonds with a maturity of 10 years or more are required to pay interest every six months; (2) Bonds with a maturity of less than 10 years, with interest paid once a year. In 2019, a special bond financing of 500 million yuan was issued for the project, with an actual interest rate of 3.63%. The interest is paid once a year with a term of 20 years.  How much is the total principal and interest due? Make sure your entire response is wrapped in JSON format.
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