12
XII
1100
The number 12 — factors and divisors
Abundant
12 = 2² × 3. It has 6 divisors, adding up to 28.
Its divisors, itself excluded, add up to more than the number.
Laid out as dots
It fits as 3 × 4. The more divisors, the closer to a square.
- Prime factors
- 2² × 3
- Divisors
- 1, 2, 3, 4, 6, 12
- Sum of divisors
- 28
- Sum without itself
- 16
- Coprime below it
- 4
- Digit sum
- 3
- Digital root
- 3
- Roman numeral
- XII
- Binary
- 1100
- Octal
- 14
- Hexadecimal
- C
- Base 36
- C
- Bits
- 4 bits
- Collatz steps
- 9 steps · peaks at 16
- Prime before
- 11
- Prime after
- 13
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 12 a prime number?
No. It breaks down into 2² × 3.
Q. What are the divisors of 12?
1, 2, 3, 4, 6, 12 — 6 divisors in all, adding up to 28.
Q. How is 12 written in binary?
1100, which is 4 bits. In hexadecimal it is C.
Q. How many Collatz steps does 12 take?
It reaches 1 in 9, peaking at 16 on the way.