Number reference
16 explained.
16: sixteen, composite, power of two; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- sixteen
- Classification
- composite
- Factors
- 1, 2, 4, 8, 16
- Prime factorization
- 2 × 2 × 2 × 2
- Square root
- 4
- Cube root
- 2.519842
- Binary
- 10000
- Octal
- 20
- Hexadecimal
- 10
- Roman numeral
- XVI
- Digit sum
- 7
- Digital root
- 7
What makes 16 notable
- Power of two. 16 = 2^4, which is why it shows up in memory sizes, image dimensions, and anything that repeatedly halves or doubles.
- Perfect square. 16 = 4², so a square of side 4 has an area of 16.
16 in everyday use
Sixteen ounces make a pound and sixteen is the base of hexadecimal, the shorthand programmers use to write bytes two digits at a time. It is the atomic number of sulfur. Early home computers and game consoles were "16-bit", and a chess player begins with sixteen pieces. In the United States a sixteenth birthday is the "sweet sixteen", and it is the age at which most states first grant a driving licence. The NCAA basketball tournament's round of sixteen borrowed the phrase.
Sixteen is both a perfect square, 4 × 4, and a perfect fourth power, 2 × 2 × 2 × 2. It is the only number that can be written as a to the power b and b to the power a with a and b different: 2⁴ and 4² are both 16. In binary it is 10000, the first five-digit number. A regular sixteen-gon can be constructed with compass and straightedge because 16 is a power of two.
Nearby numbers
How to read this page
The factor list shows every way 16 splits into equal whole-number groups — 5 divisors in total. The prime factorisation is the compact form of that same information, and the base conversions restate 16 for contexts that do not use decimal.
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