The hex color #21e40a is a light color. The web-safe version is Hex
#33CC00. A complementary color is
#DE1BF5. The grayscale version is
#5A5A5A. A 20% lighter version of the original color is
#54FF3D, and Hex
#00B100 is the 20% darker color. If the color is saturated by 10%, you get
#1BF202. If the color is desaturated by 10%, the color
#27D612 is obtained.