There are an infinite number of prime numbers beyond any fixed number of digit you could ask about. Even if we had all the computer power to find such a number what makes you think I am going to write a million digit answer. And even if I did how would you know it was right. It is not like you are going to do anything useful with this knowledge.
The reward is personal satisfaction along with bragging rights to whoever finds the next prime number. The EFF has offered rewards for prime numbers with more than 100 million decimal digits ($150,000 for 100 million or more, $250,000 for a billion or more). Note that the largest number currently known to be prime has just under 13 million decimal digits. I'm not aware of any financial rewards for finding primes with fewer than 100,000,000 digits.
One million is 1 followed by 6 zeroes - a total of 7 digits.
A boatloadThere are in infinite number or primes, and they are still being discovered. The people who discover the prime that has more than 10 million digits will win $100,000. I'm pretty sure they're getting close, something like 9.8 million digits.
There is no biggest prime number.The largest prime known at present is 243112609 - 1, a number with nearly 13 million decimal digits. It was verified by the Great Internet Mersenne Prime Search on August 23, 2008.For more information about record prime numbers, see the related link.Since we know there is no biggest number, there is no reason to believe there is such a restriction on Prime Numbers.
37
There is no limit to the infinite number of prime numbers. For example 6,079 is the 793rd prime number, but there are an infinite number of prime numbers much larger like 38,589,789,473 (thirty eight billion five hundred eighty nine million seven hundred eighty nine thousand four hundred seventy three). Prime numbers are known that have thousands of digits, far to many to list here.
30
I'm sure there are more than 2 prime numbers that are 400 digits long.
31
50
Here are some:It has only 1 and itself as unique factors. (They cannot be the same.)It ends (if 2 or more digits long) with the digits 1, 3, 7 or 9 only.
You're looking for a prime number larger than 20 with 2 or more digits that are making an even number when added. 31 or 37 will do for instance