Hex #128d80 or rgb(18,141,128) in RGB space is the tint of cyan. It has hue angle of 173.66 degrees, value = 55 and saturation = 87. #128d80 can be obtained by mixing 4 colors: 1 drop of magenta, 5 drops of blue, 3 drops of cyan, 5 drops of green.
Nearest safe hex - #009999. Below you can see the block with #128d80 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #128d80 to the mixer and play with it.