Nine hundred and eighty-seven million six hundred and fifty-four thousand three hundred and twenty-one.
ten thousand four hundred （对）
ten thousands four hundreds （错）
英式：three hundred and forty-five
美式：three hundred forty five
百万 = million
My hometown has 6 million people.
十亿 = billion
The population of China is about 1.3 billion. How about England？
2.two over three
3.two divided by three
Generally, in British English we usually connect large numbers with double or single digit figures with and, but in American English and is not used.
The facial mask brand I use is also used by two-thirds of my friends.