Number 65

65 is the natural number following 64 and preceding 66.

List of numbers — Integers << 60 61 62 63 64 65 66 67 68 69 >>
Cardinal	sixty-five
Ordinal	65th (sixty-fifth)
Factorization	<math>5 \cdot 13<math>
Roman numeral	LXV
Binary	1000001
Hexadecimal	41

Mathematics

Sixty-five is an octagonal number. It is also a Cullen number. Given 65, the Mertens function returns 0.

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

<math> \begin{bmatrix}

\end{bmatrix} <math>

This number is also the magic constant of n-Queens Problem for n = 5.

Other fields

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).
• The year AD 65, 65 BC, or 1965.