Hex #558499 or rgb(85,132,153) in RGB space is the tint of bluish cian. It has hue angle of 198.53 degrees, value = 60 and saturation = 44. #558499 can be obtained by mixing 4 colors: 5 drops of magenta, 1 drop of blue, 5 drops of cyan, 4 drops of green.
Nearest safe hex - #669999. Below you can see the block with #558499 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #558499 to the mixer and play with it.