Page "Smooth number" Paragraph 2

Note that < var > B </ var > does not have to be a prime factor.

If the largest prime factor of a number is < var > p </ var > then the number is < var > B </ var >- smooth for any < var > B </ var > ≥ < var > p </ var >.

Usually < var > B </ var > is given as a prime, but composite numbers work as well.

A number is < var > B </ var >- smooth if and only if it is < var > p </ var >- smooth, where < var > p </ var > is the largest prime less than or equal to < var > B </ var >.