Hex #55ac99 or rgb(85,172,153) in RGB space is the tint of greenish cian. It has hue angle of 166.90 degrees, value = 67 and saturation = 51. #55ac99 can be obtained by mixing 4 colors: 4 drops of cyan, 2 drops of green, 5 drops of white, 4 drops of black.
Nearest safe hex - #669999. Below you can see the block with #55ac99 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #55ac99 to the mixer and play with it.