172

This number is a composite.

There is a prime gap of 172 between the primes 140737488355609 and 140737488355781. This is the largest gap in the range [140737488353699, 140737488356209]. The first integer in this interval is the lesser element in a twin prime pair which was the largest known in 1975 while the last integer in this interval is the greater element in the next twin prime pair. [Schiffman]