As of 10/7/2015, no live official trademarks were found on USPTO.gov for the exact terms/numbers
In the West, seemingly random 9, 11, 13 number domains may seem too long and mean little to average Occidentals; heck, we don't fully understand the premise, either. However...
In Chinese culture / numerology, 5211314 means "I love you forever," and "8" is the luckiest number; double and triple 8's are even better.
The Chinese market for numerals is HUGE.
Domains Sold Separately.
Note: A Wikipedia page discussing Chinese internet slang notes that 5201314 = I love you forever.
See also WordReference.com
So we are also offering 852013148.com, 88520131488.com, and
8885201314888.com for sale here.
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