21 488:316:68 + (3 600 · 409 - 3 805 · 0) : 818 : 100 · 1

First, perform the operations inside the parentheses:
3 600 · 409 = 1 468 400
3 805 · 0 = 0

Now substitute the results back into the equation:
21 488:316:68 + (1 468 400 - 0) : 818 : 100 · 1

Now continue solving the equation:
21 488:316:68 + 1 468 400 : 818 : 100 · 1
21 488:316:68 + 1 799.51 · 1
21 488:316:68 + 1 799.51

Finally, add the two numbers together to get the final answer:
21 488:316:68 + 1 799.51 = 21 488:318:47.51

Therefore, the final answer is 21 488:318:47.51.