This is the 14th term in the canonical Mills sequence
http://primes.utm.edu/glossary/page.php?sort=MillsTheorem
http://oeis.org/A108739

The alternative (longer string) form for the number is
((((((((((((2^3+3)^3+30)^3+6)^3+80)^3+12)^3+450)^3+894)^3+3636)^3+70756)^3+97220)^3+66768)^3+300840)^3+1623568

PRP according to PFGW -b2, -b3, -b7, -b139 (and a dozen more bases), as well as BLS N+/-1 tests.

Double-check for all smaller candidates is in progress (to ascertain minimality of this term), as of July 28, 2013. There are 32110 sieved candidates below this value and all are checked at least once, as of August 3, 2013.

To be completed...