Hex #559b8e or rgb(85,155,142) in RGB space is the tint of greenish cian. It has hue angle of 168.86 degrees, value = 61 and saturation = 45. #559b8e can be obtained by mixing 4 colors: 2 drops of yellow, 1 drop of red, 3 drops of blue, 3 drops of cyan.
Nearest safe hex - #669999. Below you can see the block with #559b8e color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #559b8e to the mixer and play with it.