Hex #558098 or rgb(85,128,152) in RGB space is the tint of bluish cian. It has hue angle of 201.49 degrees, value = 60 and saturation = 44. #558098 can be obtained by mixing 4 colors: 1 drop of magenta, 4 drops of blue, 2 drops of green, 2 drops of white.
Nearest safe hex - #669999. Below you can see the block with #558098 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #558098 to the mixer and play with it.