The hex color #73e521 is a light color. The web-safe version is Hex
#66CC33. A complementary color is
#8C1ADE. The grayscale version is
#7E7E7E. A 20% lighter version of the original color is
#A6FF54, and Hex
#40B200 is the 20% darker color. If the color is saturated by 10%, you get
#72EF18. If the color is desaturated by 10%, the color
#74DB2A is obtained.