The number following twelve is thirteen, yet many people associate this number with having bad luck or meaning evil. If you’re a superstitious individual, you may typically stay away from the number thirteen a great deal. Of course, when it comes to math, this is the sixth prime number, the third center square number and is considered by mathematicians to even be a happy number. However, if you have fear regarding this number, this is considered to be a phobia by many. This tattoo design can mean varying things, and the actual meaning will depend on what the individual believes that receives the tattoo. For some people, this tattoo is a symbol of luck. That’s right; many people feel that this number can actually bring luck. However, there are also people that don’t feel quite the same and perceive this number as being more of an unlucky one or symbolic with evil. It’s not uncommon for this number to be added to a skull or other type of tattoo that is representative of evil or spirits.