The number 211
211 is the 47th prime number. Its only divisors are 1 and 211.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 211: the 47th prime number.
- 2
211 is prime, so its only factors are 1 and 211. It is the 47th prime; the next prime is 223 and the one before is 199.
- 3
The divisors add up to 212; without 211 itself that is 1, so 211 is deficient (1 is less than 211). Euler's totient φ(211) = 210 numbers up to 211 share no factor with it.
- 4
The digits of 211 add up to 4, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 39 steps to reach 1.
211 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 212 |
| Euler totient φ(n) | 210 |
| Square | 44521 |
| Cube | 9393931 |
| Square root | 14.525839 |
| Digit sum / digital root | 4 / 4 |
| Collatz steps to 1 | 39 |
| Scientific notation | 2.11 × |
211 in other forms
| Form | Value |
|---|---|
| In words | two hundred and eleven |
| Roman numerals | CCXI |
| Binary (base 2) | 11010011 |
| Octal (base 8) | 323 |
| Hexadecimal (base 16) | D3 |
| Base 3 | 21211 |
| As time | 211 seconds = 3 min 31 s |
Is 211 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | No (remainder 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 211 a prime number?
Yes. 211 is divisible only by 1 and itself.
What are the factors of 211?
1, 211.
What is 211 in binary?
11010011 (hexadecimal D3, octal 323).
What is the square root of 211?
About 14.5258.
What is 211 in Roman numerals?
CCXI.
Is 211 divisible by 3?
No. Its digits add up to 4, which is not a multiple of 3.
What is special about the number 211?
211 is the 47th prime number.