Prime numbers are a mathematical concept that you will find in most basic math courses. While they are a good thing to keep in mind and can help to speed up your math homework, it is only important to memorize as many as you can if you are planning to take a test like the SATs or the GREs for graduate school. Of course if you are a math major you will want to also memorize these. A prime number is defined as any whole number (which means no fractions or decimals) which only can be divided by 1 and itself.
A prime number is a whole number greater than 1, whose only two whole-number factors are 1 and itself. There is no biggest prime number since the further you go up in numbers, the more prime numbers you will find. Some common prime numbers are numbers such as 7, 5, 19 and 23.
