Hex #556d71 or rgb(85,109,113) in RGB space is the tint of bluish cian. It has hue angle of 188.57 degrees, value = 44 and saturation = 25. #556d71 can be obtained by mixing 4 colors: 1 drop of red, 2 drops of cyan, 2 drops of white, 4 drops of black.
Nearest safe hex - #666666. Below you can see the block with #556d71 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #556d71 to the mixer and play with it.