The hex color #644bcd is a dark color. The web-safe version is Hex
#6633CC. A complementary color is
#9BB432. The grayscale version is
#7F7F7F. A 20% lighter version of the original color is
#977EFF, and Hex
#31189A is the 20% darker color. If the color is saturated by 10%, you get
#6146D5. If the color is desaturated by 10%, the color
#6750C5 is obtained.