16
XVI
10000
The number 16 — factors and divisors
Deficient
16 = 2⁴. It has 5 divisors, adding up to 31.
Its divisors, itself excluded, add up to less than the number.
Families it belongs to
Square
A number times itself — the dots lay out as a square.
Power of two
Two multiplied by itself. Every extra bit doubles it.
Laid out as dots
It fits as 4 × 4. The more divisors, the closer to a square.
- Prime factors
- 2⁴
- Divisors
- 1, 2, 4, 8, 16
- Sum of divisors
- 31
- Sum without itself
- 15
- Coprime below it
- 8
- Digit sum
- 7
- Digital root
- 7
- Roman numeral
- XVI
- Binary
- 10000
- Octal
- 20
- Hexadecimal
- 10
- Base 36
- G
- Bits
- 5 bits
- Collatz steps
- 4 steps · peaks at 16
- Prime before
- 13
- Prime after
- 17
The grid
Ten per row, twenty rows. The filled cells are primes — you can see the multiples of 2 and 5 drop out in columns.
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Numbers either side
How to read this
- The prime factors are what the number is made of. The count and sum of divisors both follow from them.
- Add the divisors, take the number away, and you get perfect, abundant or deficient.
- The length of the binary form is the bit count. 255 taking eight digits is what a byte is.
- Collatz: halve it if even, triple it and add one if odd. The count is how many moves reach 1.
Frequently asked questions
Q. Is 16 a prime number?
No. It breaks down into 2⁴.
Q. What are the divisors of 16?
1, 2, 4, 8, 16 — 5 divisors in all, adding up to 31.
Q. How is 16 written in binary?
10000, which is 5 bits. In hexadecimal it is 10.
Q. How many Collatz steps does 16 take?
It reaches 1 in 4, peaking at 16 on the way.