Hex #558fa3 or rgb(85,143,163) in RGB space is the tint of bluish cian. It has hue angle of 195.38 degrees, value = 64 and saturation = 48. #558fa3 can be obtained by mixing 4 colors: 1 drop of magenta, 4 drops of cyan, 3 drops of white, 4 drops of black.
Nearest safe hex - #669999. Below you can see the block with #558fa3 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #558fa3 to the mixer and play with it.