the numbers are only dividable by 1 or themselves, the so called, 'prime numbers', so the next one would be 17.
11 comes next.
The number 7 comes next.
67
11
17 cause it is the next prime number
11
17
6.
59 is the next number in this series.
The next number in the series is 67.
The next number in the series is 13112221.
16.