That depends.
-- If you're rounding to the nearest ten-thousandth, it's 4.5713 .
-- If you're rounding to the nearest thousandth, it's 4.571 .
-- If you're rounding to the nearest hundredth, it's 4.57 .
-- If you're rounding to the nearest tenth, it's 4.6 .
-- If you're rounding to the nearest whole number, it's 5 .
-- If you're rounding to the nearest ten, or to any larger place, it's zero.