Hex #66a155 or rgb(102,161,85) in RGB space is the tint of grass green. It has hue angle of 106.58 degrees, value = 63 and saturation = 47. #66a155 can be obtained by mixing 4 colors: 1 drop of yellow, 5 drops of green, 5 drops of white, 4 drops of black.
Nearest safe hex - #669966. Below you can see the block with #66a155 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66a155 to the mixer and play with it.