Hex #66a099 or rgb(102,160,153) in RGB space is the tint of cyan. It has hue angle of 172.76 degrees, value = 63 and saturation = 36. #66a099 can be obtained by mixing 4 colors: 3 drops of blue, 2 drops of green, 4 drops of white, 1 drop of black.
Nearest safe hex - #669999. Below you can see the block with #66a099 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66a099 to the mixer and play with it.