You canwrite 5.73 billion as 5,730,000,000.
DLXXIII
5.73
I write 620 billion as 620 billion.
0.573 = 573/1000
Sixteen point two billion is how I would write it.
You write 3.56 billion as 3,560,000,000.
write 573 thousandths in expanded form
573/1000 or 0.573
40,300,000,000
As a number it is: 1,800,000,000 = 1.8 billion
Since you asked how I would write the number, the answer is 1031.
573 = (5 x 102) + (7 x 101) + (3 x 100)