Gets whether the cell's numeric value is displayed as date and time.
true, if the number contained in a cell is displayed as data and time; otherwise, false
Dates and times are stored in cells as numbers that are displayed according to the applied date and time formats. So, if a cell displays a date and time value, both IsDateTime and CellValue.IsNumeric properties return true.
The CellValue.NumericValue property returns the number contained in a cell, and the CellValue.DateTimeValue property returns the DateTime object, which specifies the date and time value represented by this number.