256
CCLVI
100000000
The number 256 — factors and divisors
Deficient
256 = 2⁸. It has 9 divisors, adding up to 511.
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 16 × 16. The more divisors, the closer to a square.
- Prime factors
- 2⁸
- Divisors
- 1, 2, 4, 8, 16, 32, 64, 128, 256
- Sum of divisors
- 511
- Sum without itself
- 255
- Coprime below it
- 128
- Digit sum
- 13
- Digital root
- 4
- Roman numeral
- CCLVI
- Binary
- 100000000
- Octal
- 400
- Hexadecimal
- 100
- Base 36
- 74
- Bits
- 9 bits
- Collatz steps
- 8 steps · peaks at 256
- Prime before
- 251
- Prime after
- 257
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 256 a prime number?
No. It breaks down into 2⁸.
Q. What are the divisors of 256?
1, 2, 4, 8, 16, 32, 64, 128, 256 — 9 divisors in all, adding up to 511.
Q. How is 256 written in binary?
100000000, which is 9 bits. In hexadecimal it is 100.
Q. How many Collatz steps does 256 take?
It reaches 1 in 8, peaking at 256 on the way.