Hex #669599 or rgb(102,149,153) in RGB space is the tint of cyan. It has hue angle of 184.71 degrees, value = 60 and saturation = 33. #669599 can be obtained by mixing 3 colors: 1 drop of cyan, 2 drops of white, 2 drops of black.
Nearest safe hex - #669999. Below you can see the block with #669599 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #669599 to the mixer and play with it.