This number is a prime.
Oscar Volpatti of Italy discovered that p = 2856646544865959 is the smallest in a twin pair, p and p+2, that produce three other twin pairs by recursively applying the formula [p*p(+1)*(p+2)-1, p*p(+1)*(p+2)+1]. The size of this prime was predicted with help from the Bateman-Horn conjecture and it's possible the first 5-set may be in the range of 10^23 or greater. See PC3. [Rivera]