A full reptend prime is a special type of prime number (a number that can only be divided by itself and one). Full reptend primes are special because when you keep dividing them by the same number, the decimal part of the answer keeps repeating over and over. For example, if you divide 7 by 3, the answer is 2.3333333 and it keeps going on and on like that. So, full reptend primes are special prime numbers that have never ending decimal parts when you divide them by the same number.