Hex #558580 or rgb(85,133,128) in RGB space is the tint of cyan. It has hue angle of 173.75 degrees, value = 52 and saturation = 36. #558580 can be obtained by mixing 4 colors: 3 drops of blue, 2 drops of green, 4 drops of white, 3 drops of black.
Nearest safe hex - #669999. Below you can see the block with #558580 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #558580 to the mixer and play with it.