Vachmi
What are Prime Numbers
A prime number is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. 7 is prime because the only ways of writing it as a product, 1 × 7 or 7 × 1, involve 7 itself. e.g. 2, 3, 5, 7, 11, 13, 17, 19, 23 are some of the first prime numbers.
Is 0 a prime number?
Zero is neither prime nor composite. Since any number times zero equals zero, there are an infinite number of factors for a product of zero. A composite number must have a finite number of factors.
Is 1 a prime number?
One is also neither prime nor composite.
What are Twin Primes
A twin prime is a prime number that is either 2 less or 2 more than another prime number. For example, either member of the twin prime pair (17, 19) or (41, 43).
In other words, a twin prime is a prime that has a prime gap of two.
The first several twin prime pairs are
(3, 5), (5, 7), (11, 13), (17, 19), (29, 31), (41, 43), (59, 61), (71, 73), (101, 103), (107, 109), (137, 139), ...
Usually the pair (2, 3) is not considered to be a pair of twin primes.
Smallest Prime Number
2 is the smallest prime number.
Largest Prime Number
The largest prime number discovered so far is 2 raised to the 57,885,161st power minus 1, or $2^{57,885,161}$ - 1. It is 17,425,170 digits long.
Refer Prime numbers worksheet here