@COMMA

@COMMA[n] :  Returns the number with commas (or the appropriate Thousands character for your current country setting) inserted where appropriate.

Note: Some variable functions can directly generate a numeric result with appropriate thousand separators if you add a c to their scale parameter.

Examples:

echo %@comma[12345678]

echo %@comma[0.12345678]

echo %@comma[%_xpixels]

See also: @CONVERT, @FORMAT, @FORMATN.