ISLOGICAL, ISNONTEXT, ISNUMBER, ISTEXT – DAX Guide
ISLOGICAL: Checks whether a value is a logical value (TRUE or FALSE).
https://dax.guide/islogical/
ISNONTEXT: Checks whether a value is not text.
https://dax.guide/isnontext/
ISNUMBER: Checks whether a value is a number.
https://dax.guide/isnumber/
ISTEXT: Checks whether a value is text.
https://dax.guide/istext/