Hex #558f95 or rgb(85,143,149) in RGB space is the tint of cyan. It has hue angle of 185.63 degrees, value = 58 and saturation = 43. #558f95 can be obtained by mixing 4 colors: 1 drop of red, 4 drops of cyan, 3 drops of white, 4 drops of black.
Nearest safe hex - #669999. Below you can see the block with #558f95 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #558f95 to the mixer and play with it.