178571domain: NPropertiesPrimalityPrimeyesAppears in sequencesMinimum number k for which the digital sum of k*n is 2*n.at n=28A147822SanD-68 primes p: such that p+d is also prime and sum of digits A007953(p(p+d)) = d, with d = 68.at n=39A307474Prime numbersat n=16209