Hex #66a755 or rgb(102,167,85) in RGB space is the tint of grass green. It has hue angle of 107.56 degrees, value = 65 and saturation = 49. #66a755 can be obtained by mixing 4 colors: 1 drop of yellow, 1 drop of magenta, 1 drop of cyan, 2 drops of green.
Nearest safe hex - #669966. Below you can see the block with #66a755 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66a755 to the mixer and play with it.