six hundred twenty-five million.
Don't stick an "and" in there (not "six-hundred and 25 million), as "and" usually denotes the decimal place (i.e. 6.25 is six and 25 hundredths)
Six hundred and twenty five million.
Six hundred twenty five million
625 000 000
This number is four quadrillion.
Six hundred billion.
Thirty-five billion.
Six million.
twelve million
fifteen million
Two hundred eighty million.
Six hundred twenty-five percent.
625 = 6.25 × 102