From online help:
ToText (x, y, z)
x is a Number or Currency value to be converted into a text string; it can be a whole or fractional value.
y is a whole number indicating the number of decimal places to carry the value in x to (This argument is optional.).
z is a single character text string indicating the character to be used to separate thousands in x. Default is the character specified in your International or Regional settings control panel. (This argument is optional.)
"" is an empty string so no seperator is used