1613902553

This number is a prime.

The start of eighteen consecutive primes with symmetrical gaps around the center. Here is a graphic display of the gaps between these primes:

         x                   x
         x                   x
         x                   x
         x                   x
         x                   x
         x                   x
         x                   x
         x                   x
         x x               x x
         x x               x x
         x x               x x
         x x               x x
         x x   x       x   x x
         x x   x       x   x x
         x x   x       x   x x
         x x   x       x   x x
         x x   x       x   x x
         x x   x       x   x x
         x x   x       x   x x
         x x   x       x   x x
   x     x x   x       x   x x     x
   x     x x   x       x   x x     x
   x x x x x x x x   x x x x x x x x
   x x x x x x x x   x x x x x x x x
   x x x x x x x x   x x x x x x x x
   x x x x x x x x   x x x x x x x x
   x x x x x x x x x x x x x x x x x
                   .
                 .   .
       1613902649     1613902651

Note the gap of one between the twin primes at the center.

[McCranie]