Hex #558288 or rgb(85,130,136) in RGB space is the tint of cyan. It has hue angle of 187.06 degrees, value = 53 and saturation = 38. #558288 can be obtained by mixing 4 colors: 2 drops of red, 5 drops of cyan, 3 drops of white, 5 drops of black.
Nearest safe hex - #669999. Below you can see the block with #558288 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #558288 to the mixer and play with it.