The University is given a gift of $$500000$ for the construction of a School of Management building. The University invests the gift into an account for future use.

The University receives $8\mathrm{.}00\%$ on the money for $7$ years then the rate drops to $6\mathrm{.}40\%.$ If the building is constructed $23$ years after the gift was received, how much is in the fund at that time?

$

Do not use dollar signs or commas in your answer. Include two decimals in your answer.