Text values and errors are not converted and pass through unaffected.

you’ve got the option to use the T function to remove values that are not text.

The T function is provided for compatibility with other spreadsheet programs.

Excel formula: Translate letters to numbers

The N function can be used to convert TRUE and FALSE to 1 and 0 respectively.

When given a text value, the N function returns zero.

Excel formula: List sheet names with formula

Excel N function