Delicate prime

A delicate prime (also known as weakly prime) is a special type of prime number, where if any of its digits are changed to another digit (from 0 to 9), it is no longer a prime number.

Examples of Delicate Primes

The smallest delicate prime number is the number 294001. It is a prime number, but if you change any of the digits (2, 9, 4, 0, 0, or 1) to another number, the new number will not be prime. For example:

  • If you change the first digit from 2 to 1, you get 194001, which is not a prime number.
  • If you change the second digit from 9 to 8, you get 284001, which is also not a prime number.

The first 20 delicate primes are 294001, 505447, 584141, 604171, 971767, 1062599, 1282529, 1524181, 2017963, 2474431, 2690201, 3085553, 3326489, 4393139, 5152507, 5564453, 5575259, 6173731, 6191371, and 6236179.[1]

Why are they special?

Delicate primes are special because even a small change in their digits turns them into a composite number (a number that is not prime). This makes them rare and interesting to mathematicians.

Finding delicate primes

It is not easy to find delicate primes because there are not many of them. Mathematicians use computers and special methods to search for these numbers.

References

  1. "Numbers Aplenty".