Sunday Times Teaser 2815 – PIN in the Middle
by Nick MacKinnon
Published: 4 September 2016 (link)
For Max Stout’s various accounts and cards he has nine different 4-digit PINs to remember. For security reasons none of them is the multiple of another, and none is an anagram of another. He has written these PINs in a 3-by-3 array with one PIN in each place in the array. It turns out that the product of the three PINs in any row, column or main diagonal is the same. In fact there are just two different prime numbers that divide into this product.
What is the PIN in the middle position of the array?