The hex color #3721cc is a dark color. The web-safe version is Hex
#3333CC. A complementary color is
#C8DE33. The grayscale version is
#616161. A 20% lighter version of the original color is
#6A54FF, and Hex
#040099 is the 20% darker color. If the color is saturated by 10%, you get
#331BD7. If the color is desaturated by 10%, the color
#3B27C1 is obtained.