921601domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrime divisors of (10^9)^(10^9) + 1 = 10^9000000000 + 1.at n=2A076670Primes p such that (p+3839)/3840 is also a prime number.at n=20A162141Prime numbers with locations of right angle turns in the Ulam square spiral that are vertices of isosceles right triangles.at n=10A270269Prime numbersat n=72849