In the number 854, 263, 189, what number tells the number of million

is the answer is 54?

I'm not quite sure what you are asking. With the spaces after the commas, they seem like three separate numbers.

854,263,189 is said as "eight hundred fifty-four million, two hundred sixty-three thousand, one hundred eighty-nine." If this is so, there are 854 million.

I hope this helps. Thanks for asking.