218
CCXVIII
11011010
The number 218 — factors and divisors
Deficient
218 = 2 × 109. It has 4 divisors, adding up to 330.
Its divisors, itself excluded, add up to less than the number.
Laid out as dots
It fits as 2 × 109. The more divisors, the closer to a square.
- Prime factors
- 2 × 109
- Divisors
- 1, 2, 109, 218
- Sum of divisors
- 330
- Sum without itself
- 112
- Coprime below it
- 108
- Digit sum
- 11
- Digital root
- 2
- Roman numeral
- CCXVIII
- Binary
- 11011010
- Octal
- 332
- Hexadecimal
- DA
- Base 36
- 62
- Bits
- 8 bits
- Collatz steps
- 114 steps · peaks at 9,232
- Prime before
- 211
- Prime after
- 223
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 218 a prime number?
No. It breaks down into 2 × 109.
Q. What are the divisors of 218?
1, 2, 109, 218 — 4 divisors in all, adding up to 330.
Q. How is 218 written in binary?
11011010, which is 8 bits. In hexadecimal it is DA.
Q. How many Collatz steps does 218 take?
It reaches 1 in 114, peaking at 9,232 on the way.