Hex #404400 or rgb(64,68,0) in RGB space is the tint of yellow. It has hue angle of 63.53 degrees, value = 27 and saturation = 100. #404400 can be obtained by mixing 3 colors: 2 drops of red, 3 drops of green, 3 drops of black.
Nearest safe hex - #333300. Below you can see the block with #404400 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #404400 to the mixer and play with it.