Hex #66df88 or rgb(102,223,136) in RGB space is the tint of bluish green. It has hue angle of 136.86 degrees, value = 87 and saturation = 54. #66df88 can be obtained by mixing 4 colors: 2 drops of yellow, 4 drops of cyan, 5 drops of green, 4 drops of white.
Nearest safe hex - #66cc99. Below you can see the block with #66df88 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66df88 to the mixer and play with it.