A phone dial pad with empty squares

Book Hint:

Pick up your phone and try to remember your high school math lessons.

Hint One

• 16 squared is 256
• utopia – auto = pi

Hint Two

• Check his old phone number in puzzle 14
• you’ve created a ‘new’ phone call pad with the numbers from hint one
• pretending a real call pad was superimposed on your new one, what number would Arthur have?

Hint Three

• Call him on cypher.center/cyphone at the new number

Solution

• order

Clue 17

• touch