Hex #66c533 or rgb(102,197,51) in RGB space is the tint of grass green. It has hue angle of 99.04 degrees, value = 77 and saturation = 74. #66c533 can be obtained by mixing 4 colors: 4 drops of yellow, 2 drops of cyan, 3 drops of green, 1 drop of black.
Nearest safe hex - #66cc33. Below you can see the block with #66c533 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66c533 to the mixer and play with it.