Do you use commas when you write digits after the decimal point?

Question

So, for example the number 123,456.7654321

Would you write

one hundred twenty-three thousand, four hundred fifty-six and seven million six hundred fifty-four thousand three hundred twenty-one ten-millionths (without commas after the decimal point)

or

one hundred twenty-three thousand, four hundred fifty-six and seven million, six hundred fifty-four thousand, three hundred twenty-one ten-millionths (with commas after the decimal point)

Also, are the digits in front of the decimal point correctly written? I think they are.

Answer 1

N0p3.

Answer 2

Your second way of doing it (with commas) is correct. Without the commas, it gets grammatically jumbled and hard to read and comprehend. Keep the commas!

Answer 3

in front they are. not sure about after the point though. maybe you should stick writing in number form rather than words??  

Answer 4

No, you don't use commas after the decimal point, yes your integer is correctly written.