Hex #66aeaa or rgb(102,174,170) in RGB space is the tint of cyan. It has hue angle of 176.67 degrees, value = 68 and saturation = 41. #66aeaa can be obtained by mixing 4 colors: 1 drop of yellow, 2 drops of blue, 1 drop of cyan, 1 drop of white.
Nearest safe hex - #669999. Below you can see the block with #66aeaa color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66aeaa to the mixer and play with it.