#36 PRETTY NUMBERS

A number N is called a 'pretty number' if the following requirement is met:

All numbers n<N that have no common divisor with N are prime numbers.

What is the highest existing 'pretty number'?

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Example:

'8' is a pretty number because:
2,4 and 6 share the common divisor '2' with '8'
AND
3,5 and 7 have no common divisor with '8' and are prime numbers.

Correct answer: 30

Explanation: