Hex #557d80 or rgb(85,125,128) in RGB space is the tint of cyan. It has hue angle of 184.19 degrees, value = 50 and saturation = 34. #557d80 can be obtained by mixing 3 colors: 1 drop of cyan, 2 drops of white, 3 drops of black.
Nearest safe hex - #666699. Below you can see the block with #557d80 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #557d80 to the mixer and play with it.