Hex #66d777 or rgb(102,215,119) in RGB space is the tint of bluish green. It has hue angle of 129.03 degrees, value = 84 and saturation = 53. #66d777 can be obtained by mixing 4 colors: 4 drops of yellow, 1 drop of blue, 4 drops of cyan, 1 drop of green.
Nearest safe hex - #66cc66. Below you can see the block with #66d777 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66d777 to the mixer and play with it.