2277659domain: NPropertiesPrimalityPrimeyesAppears in sequencesLower primes p1 in a twin pair such that sum of p1 and p2 yields average a1 of twin prime pairs and product of 2*a1 is another average of twin prime pairs.at n=11A178421Safe primes that are also highly cototient numbers.at n=20A209193Prime numbersat n=168009