Hex #559888 or rgb(85,152,136) in RGB space is the tint of greenish cian. It has hue angle of 165.67 degrees, value = 60 and saturation = 44. #559888 can be obtained by mixing 4 colors: 1 drop of magenta, 5 drops of blue, 5 drops of green, 4 drops of white.
Nearest safe hex - #669999. Below you can see the block with #559888 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #559888 to the mixer and play with it.