991999

Properties

Appears in sequences

• Primes that contain digits 1 and 9 only.at n=26A020457
• Near-repdigit primes with 9 as repeated digit.at n=26A105975
• Emirps with digits 1 and 9 only.at n=10A155507
• Lesser of emirps (pairs) with digits 1 and 9 only.at n=5A155508
• Primes composed of digit {1,9} and with digit sum 9*k+1.at n=8A164890
• The smaller member of a near-repdigit emirp pair.at n=19A173595
• Primes consisting of a single 1 and at least one copy of some other digit.at n=32A325934
• Prime numbersat n=77927