Hex #669555 or rgb(102,149,85) in RGB space is the tint of grass green. It has hue angle of 104.06 degrees, value = 58 and saturation = 43. #669555 can be obtained by mixing 4 colors: 1 drop of yellow, 4 drops of green, 5 drops of white, 5 drops of black.
Nearest safe hex - #669966. Below you can see the block with #669555 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #669555 to the mixer and play with it.