Hex #66d84d or rgb(102,216,77) in RGB space is the tint of grass green. It has hue angle of 109.21 degrees, value = 85 and saturation = 64. #66d84d can be obtained by mixing 4 colors: 3 drops of yellow, 2 drops of cyan, 4 drops of green, 1 drop of white.
Nearest safe hex - #66cc66. Below you can see the block with #66d84d color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66d84d to the mixer and play with it.