31131...13113 (103-digits)

This number is a prime.

                                        311 3113113113 1131131131 1311311311
3113113113 1131131131 1311311311 3113113113 1131131131 1311311311 3113113113

Just showing those entries submitted by 'Patterson': (Click here to show all)

This is a prime palindrome of prime length with prime digital sum that also has the property that each substring of adjacent digits of length 2 or 3 is also prime. [Patterson]