I am suspicious that you are writing the value with the dollar-sign and commas included.   Try omitting all this, and simply write the number, 77777.   It’s Excel’s responsibility to format the content of the cell, as currency or what-have-you.

Excel has a certain amount of “de-formatting” that it applies in its user interface to keep the accountants happy, but these do not hold when you are directly writing data into the spreadsheet file.