Hex #66a74d or rgb(102,167,77) in RGB space is the tint of grass green. It has hue angle of 103.33 degrees, value = 65 and saturation = 54. #66a74d can be obtained by mixing 4 colors: 1 drop of red, 5 drops of green, 3 drops of white, 1 drop of black.
Nearest safe hex - #669966. Below you can see the block with #66a74d color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66a74d to the mixer and play with it.