i kinda dislike round numbers
Nine thousand nine-hundred ninety-nine (9999) is the natural number following 9998 and preceding 10000.
9999 can be used as a divisor to generate 4-digit decimal recurrences. For example, 1234 / 9999 = 0.123412341234... .
9999 is an auspicious number in Chinese folklore. The original layout for the Forbidden City had 9999 rooms. Valerie Hansen in 'Negotiating Daily Life in Traditional China: How Ordinary People Used Contracts, 600-1400 (Yale University Press, 1995) mentioned that Chinese tomb contracts often involved being buried with 9999 coins, relational notion to Joss paper, as it was believed the dead would need that amount to buy the burial plot from the Earth goddess.