For this case we must make a conversion. By definition, we have to:
1 liter equals 1000 milliliters.
So, we make a rule of three:
1L ------------> 1000mL
x ---------------> 1580mL
Where the variable "x" represents the amount of liters equivalent to 1580 milliliters.

Thus, 1580 milliliters equals 1.58 liters.
Anwer:
1.58 liters