Hex #66c54d or rgb(102,197,77) in RGB space is the tint of grass green. It has hue angle of 107.50 degrees, value = 77 and saturation = 61. #66c54d can be obtained by mixing 4 colors: 3 drops of yellow, 1 drop of red, 3 drops of cyan, 3 drops of green.
Nearest safe hex - #66cc66. Below you can see the block with #66c54d color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66c54d to the mixer and play with it.