Hex #15315d or rgb(21,49,93) in RGB space is the tint of blue. It has hue angle of 216.67 degrees, value = 36 and saturation = 77. #15315d can be obtained by mixing 4 colors: 1 drop of red, 5 drops of blue, 1 drop of cyan, 5 drops of black.
Nearest safe hex - #003366. Below you can see the block with #15315d color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #15315d to the mixer and play with it.