$$a$$ and $$b$$ are natural numbers such that $$a < b$$ and $$a \times b = 2002$$. Then the minimum value of $$b - a$$ is ______.

Factorising, $$2002 = 2 \times 7 \times 11 \times 13$$, and the difference $$b - a$$ is least when the two factors are as close as possible to $$\sqrt{2002} \approx 44.7$$. The closest divisor pair is $$26 \times 77$$, since the neighbouring pairs $$22 \times 91$$ and $$14 \times 143$$ are further apart. Hence the minimum value is $$77 - 26 = 51$$.