Again, just press the space bar or click the green flag to check if your number is a Mersenne Prime.
A Mersenne prime is a type of prime number (a number with not factors other than itself and one). If a prime =2^p -1, where p is a prime, than it is a Mersenne prime. For example 2^5-1 is 31, which is prime, so31 is a Mersenne prime. However, 5+1=6, which is not a power of two, so it is not a Mersenne prime All me.