Hex #66c444 or rgb(102,196,68) in RGB space is the tint of grass green. It has hue angle of 104.06 degrees, value = 77 and saturation = 65. #66c444 can be obtained by mixing 4 colors: 2 drops of yellow, 1 drop of blue, 5 drops of green, 2 drops of white.
Nearest safe hex - #66cc33. Below you can see the block with #66c444 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66c444 to the mixer and play with it.