You can register numbers as trademarks, and some numbers are still available.
- The number 1 is a registered trademark of Dale Ernhardt (http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=75439039).
- The number (3) (in parentheses) is a registered trademark of Level 3 Communications (http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=75853561).
- The number 4 is a registered trademark of Swingline (as in staplers) (http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=72124386).
- The number 5 is a registered trademark of Chanel (as in Chanel No. 5 perfume) (http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=73788555).
- The number 31 is a registered trademark of Baskin-Robbins (as in flavors of ice cream) (http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=72172718).
- The number “33” (in quotes) is a registered trademark of Latrobe Brewing Company (as in the mysterious number on Rolling Rock beer) (http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=74597692).
- The number 57 is a registered trademark of the H.J. Heinz Company (as in Heinz 57 sauce) (http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=73127572).
- The number 501 is a registered trademark of Levi Strauss & Co. (as in blue jeans) (http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=73768165).
- The number 747 is a registered trademark of Boeing (as in planes) (http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=72350803).
- The number 8675309 is a registered trademark, but not of Tommy Tutone (http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=75717545).
Most of the numbers 1-99 are registered trademarks. The numbers 16, 26, 27, 28, 34, 36, 41, 42, 46, 49, 52, 54, 55, 58, 59, 60, 61, 62, 64, 65, 66, 68, 70, 71, 72, 73, 74, 78, 79, 81, 83, 85, 86, 89, 93, 94, 95, 96, and 97 are not (yet) registered trademarks. I expected that 11 would be registered to Spinal Tap, but it wasn’t. I expected 42 (the answer to everything) to be registered (in the spirit of “The Hitchhiker’s Guide to the Universe”), but it wasn’t. And I expected 66 to be registered (as in Route 66 or Phillips 66), but it wasn’t. If you are using a number to identify your goods or services, than you, too, may be able to register the number as a trademark.