Hex #556971 or rgb(85,105,113) in RGB space is the tint of bluish cian. It has hue angle of 197.14 degrees, value = 44 and saturation = 25. #556971 can be obtained by mixing 3 colors: 3 drops of red, 4 drops of cyan, 2 drops of black.
Nearest safe hex - #666666. Below you can see the block with #556971 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #556971 to the mixer and play with it.