Hex #55ac39 or rgb(85,172,57) in RGB space is the tint of grass green. It has hue angle of 105.39 degrees, value = 67 and saturation = 67. #55ac39 can be obtained by mixing 4 colors: 3 drops of yellow, 2 drops of cyan, 2 drops of green, 2 drops of black.
Nearest safe hex - #669933. Below you can see the block with #55ac39 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #55ac39 to the mixer and play with it.