6611

6611 = 11 x 601.

6611 is a value of n such that the nth Cullen number is prime (A005849).

6611 is the number of primes between 3,400,000 and 3,500,000 (A038825).

6611 is a potential magic constant of 9 x 9 magic squares composed of consecutive primes (A191679).

6611 divides 32¹⁰ - 1. It is also a divisor of 2⁵⁰ - 1 (A003554).

Source: What's Special About This Number?