Today is Sunday. What's the day after 1997?

Today is Sunday. What's the day after 1997?

Tuesday 1997 is the 1997 power of 7 * 285 + 21997, which can be regarded as the 1997 power of (7 * 285 + 2). According to the quadratic term theorem, the first 1997 times of 2 are all multiples of 7. Let's judge that the remainder of the first divisional 7 of 22 is 2; the remainder of the second divisional 7 of 2 is 4; the remainder of the third divisional 7 of 2 is 1; the remainder of the fourth divisional 7 of 2 is 1