Smooth numbers are used in cryptography to provide fast factorization methods. A smooth number is defined as a number whose factors are smaller than a given value. For a 5-smooth number, the factors must be equal to five or less.
Every value, apart from prime numbers, can be reduced to the multiplication of prime numbers. For example 102 is equal to 2 ×3 ×17 [here]. A value of 56 is 2 ×2 ×2 ×7, and is thus 7-smooth, but not 3-smooth…
