3917

3917 is a prime number.

3917 and 3919 form a twin prime pair.

3917 has a representation as a sum of two squares: 3917 = 14² + 61².

3917 is the hypotenuse of a primitive Pythagorean triple: 3917² = 1708² + 3525².

3917 divides 66¹¹ - 1.

Source: Prime Curios!