Hex #558998 or rgb(85,137,152) in RGB space is the tint of bluish cian. It has hue angle of 193.43 degrees, value = 60 and saturation = 44. #558998 can be obtained by mixing 4 colors: 2 drops of yellow, 1 drop of magenta, 4 drops of blue, 2 drops of cyan.
Nearest safe hex - #669999. Below you can see the block with #558998 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #558998 to the mixer and play with it.