Original brain teaser

1. Yesterday, Zimi received a gift from his junior, an unconventional watch made up of 13 digits. (br) Comparing it with his own time, Zimi found that while the normal watch showed 11:30, the unconventional watch showed 12:36. (br) Here's the question: After 72 hours on the normal watch, what time will the unconventional watch show? (br) 2. It is known that two identical numbers N multiplied together equal 12345678987654321. (br) Try to write down the number of digits of N and the exact value of N. (br)