In the American system, 1000 million is a billion, so it is two billion or 2 billion; in numbers it is 2,000,000,000.
Write 1.98 million is 1,980,000
2000 million is two billion.
2000 * 100 million = 200 billion.
To write out four hundred million, you would write 400,000,000. This is the numerical representation of four hundred million in standard form. In words, you would write it as "Four hundred million."
I would write it as 2.06 million - exactly as in the question.