Hex #557c7d or rgb(85,124,125) in RGB space is the tint of cyan. It has hue angle of 181.50 degrees, value = 49 and saturation = 32. #557c7d can be obtained by mixing 4 colors: 5 drops of magenta, 4 drops of cyan, 5 drops of green, 1 drop of black.
Nearest safe hex - #666666. Below you can see the block with #557c7d color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #557c7d to the mixer and play with it.