Hex #668739 or rgb(102,135,57) in RGB space is the tint of olive. It has hue angle of 85.38 degrees, value = 53 and saturation = 58. #668739 can be obtained by mixing 4 colors: 4 drops of yellow, 2 drops of red, 5 drops of blue, 4 drops of green.
Nearest safe hex - #669933. Below you can see the block with #668739 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #668739 to the mixer and play with it.