Hex #153f64 or rgb(21,63,100) in RGB space is the tint of blue. It has hue angle of 208.10 degrees, value = 39 and saturation = 79. #153f64 can be obtained by mixing 4 colors: 1 drop of red, 4 drops of blue, 2 drops of cyan, 5 drops of black.
Nearest safe hex - #003366. Below you can see the block with #153f64 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #153f64 to the mixer and play with it.