The largest known prime number to date is .
It was found on 7 December 2018 and has 24,862,048 digits. It is also the 51st known Mersenne Prime. It is more than one and a half million digits larger than the previous record prime number.
Prime numbers are positive integers that have exactly 2 factors, that is 1 and itself. For example, 7 is a prime number because its only factors are 1 and 7.
The first few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, and so on. Please note that 1 is not prime because it only has one factor.
You can check whether a number is a prime or not by entering the number below. If the only prime factor of that number is itself, then it's a prime number.
Prime factors are factors of an integer that are prime. Prime factors can be used to find Highest Common Factor (a.k.a Greatest Common Divisor or GCD) and Lowest Common Multiple of two or more integers.
To find the prime factors of a number we can repeatedly divide by prime numbers.
For example to find the prime factors of 36, we would do the folowing steps.
Another example to find the prime factors of 42.