277

277 is the 59th prime number, and a regular prime.It is the smallest prime p such that the sum of the inverses of the primes up to p is greater than two.Since 59 is itself prime, 277 is a super-prime.59 is also a super-prime (it is the 17th prime), as is 17 (the 7th prime). However, 7 is the fourth prime number, and 4 is not prime. Thus, 277 is a super-super-super-prime but not a super-super-super-super-prime. It is the largest prime factor of the Euclid number 510511 = 2 × 3 × 5 × 7 × 11 × 13 × 17 + 1