This number is a prime.
Largest distinct-digit prime p for which 10*p+1, 10*p+3, 10*p+7 and 10*p+9 are primes. [Gupta]
Largest distinct-digit prime p for which 10*p+1, 10*p+3, 10*p+7 and 10*p+9 are primes. [Gupta]