521481197domain: NPropertiesPrimalityPrimeyesAppears in sequencesInitial members of prime octuplets (p, p+2, p+6, p+12, p+14, p+20, p+24, p+26).at n=21A022012Initial members of prime nonuplets (p, p+2, p+6, p+12, p+14, p+20, p+24, p+26, p+30).at n=5A022546Initial members of prime 9-tuplets (or nonuplets).at n=14A257125Prime numbersat n=27426265