Sixty-five

Sixty-five (65, LXV) is a natural number following sixty-four and preceding sixty-six. It is a triangular number, and a Cullen number as well as a composite number with the divisors being 5 and 13. Its factorization is:

This number is the magic result of 5 by 5 magic square:

Sixty-five is also:

• The atomic number of terbium, a lanthanide.
• A common speed limit, in miles per hour, for freeways in many U.S. states.
• The designation of Interstate 65, a freeway that runs from Alabama to Indiana.
• The code for international direct dial phone calls to Singapore.
• The standard age for retirement in the UK, Germany and other countries.
• The registry of the U.S. Navy's nuclear aircraft carrier USS Enterprise (CVN-65).

This article is about the number 65. For the year AD 65, see 65.