Primality proof for n = 40207916671986113857497328863224192623039803613950016309508083637168042126527904219:

Take b = 2.

b^(n-1) mod n = 1.

5928943045730601679673230900230929495199307291013218575943 is prime.
b^((n-1)/5928943045730601679673230900230929495199307291013218575943)-1 mod n = 32600281089019436517393847026203016303463400431138518382462538914553687579633202324, which is a unit, inverse 26683675024799268156093763855759540741140619952695793063898680775380506633826642207.

(5928943045730601679673230900230929495199307291013218575943) divides n-1.

(5928943045730601679673230900230929495199307291013218575943)^2 > n.

n is prime by Pocklington's theorem.