Hex #669c55 or rgb(102,156,85) in RGB space is the tint of grass green. It has hue angle of 105.63 degrees, value = 61 and saturation = 46. #669c55 can be obtained by mixing 4 colors: 2 drops of yellow, 1 drop of blue, 1 drop of cyan, 1 drop of black.
Nearest safe hex - #669966. Below you can see the block with #669c55 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #669c55 to the mixer and play with it.