My local greengrocer is a would-be mathematician.

He likes to arrange his apples in nice rows.

However, when he lays his apples in rows of 3 he has one left over.

When he lays them in rows of 5 he also has one left over.

Remarkably he also has one left over when he arranges them in rows of 7 and 9.

11 seems to be the magic number, for, in rows of 11 there are no apples left over.

How many apples does the greengrocer have?