This number is a composite.
1268759440032 is the earliest sum S of the first k primes, that is "sandwiched" in the middle of a pair of twin primes P1 and P2. This occur for k=425373, primes go from 2 to 6196019 and the twin primes are 1268759440031 and 1268759440033. Moreover, S, P1 and P2 are pandigitals. [Rivera]