My favorite number is 73939133. This number has a remarkable property—it is a right-truncatable prime. It is a prime number, and if we remove the rightmost digit, the remaining number is still a prime. If we continue this process, removing one digit at a time from the right, every resulting number remains prime. Moreover, 73939133 is the known right-truncatable prime.
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7
73
739
7393
73939
739391
7393913
73939133