Hex #66a491 or rgb(102,164,145) in RGB space is the tint of greenish cian. It has hue angle of 161.61 degrees, value = 64 and saturation = 38. #66a491 can be obtained by mixing 4 colors: 3 drops of yellow, 1 drop of magenta, 3 drops of blue, 3 drops of cyan.
Nearest safe hex - #669999. Below you can see the block with #66a491 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66a491 to the mixer and play with it.