Hex #155a56 or rgb(21,90,86) in RGB space is the tint of cyan. It has hue angle of 176.52 degrees, value = 35 and saturation = 77. #155a56 can be obtained by mixing 4 colors: 1 drop of magenta, 5 drops of blue, 4 drops of green, 2 drops of black.
Nearest safe hex - #006666. Below you can see the block with #155a56 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #155a56 to the mixer and play with it.