Geek Challenge: Primetime Telephone Numbers

Geek Challenge: Primetime Telephone Numbers

I was listening to the radio, and some self-proclaimed geek said that her phone number was "seven prime numbers."

At first, I interpreted this as "seven prime digits," which is probably what she meant.

But then it got me thinking, 23 has three prime numbers in it (2, 3, and 23), and 373 contains six primes!

The most primes you can pack into a seven-digit number is 22, so what number contains 22 primes? 

Remember: neither 0 nor 1 are prime; and 5003 contains 5 primes (5, 3, 03, 003, and 5003).

Bonus: What if her phone number was ten digits long? How many primes can you pack into a ten digit number?

The number 2765073 contains nine prime numbers

The solution with the most complete analysis will be this month's Geek Challenge winner!

Submit responses to by June 1, 2018.

Check out any previous Geek Challenges you might have missed!


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