The number 1211
1211 is a composite number with 4 divisors. Its prime factorisation is 7 × 173. Divisors (4): 1, 7, 173, 1211.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1211: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 7 × 173, the product of two primes.
- 2
1211 is composite. Its prime factorisation is
- 3
The divisors add up to 1392; without 1211 itself that is 181, so 1211 is deficient (181 is less than 1211). Euler's totient φ(1211) = 1032 numbers up to 1211 share no factor with it.
- 4
The digits of 1211 add up to 5, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 70 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1211 = 7 \times 173 \]
1211 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1392 |
| Euler totient φ(n) | 1032 |
| Square | 1466521 |
| Cube | 1775956931 |
| Square root | 34.799425 |
| Digit sum / digital root | 5 / 5 |
| Collatz steps to 1 | 70 |
| Scientific notation | 1.211 × |
1211 in other forms
| Form | Value |
|---|---|
| In words | one thousand two hundred and eleven |
| Roman numerals | MCCXI |
| Binary (base 2) | 10010111011 |
| Octal (base 8) | 2273 |
| Hexadecimal (base 16) | 4BB |
| Base 3 | 1122212 |
| As time | 1211 seconds = 20 min 11 s |
Is 1211 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 2) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (1211 ÷ 7 = 173) | 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 5) | 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 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1211 a prime number?
No. 1211 = 7 × 173, so it is divisible by 7.
What are the factors of 1211?
1, 7, 173, 1211.
What is 1211 in binary?
10010111011 (hexadecimal 4BB, octal 2273).
What is the square root of 1211?
About 34.7994.
What is 1211 in Roman numerals?
MCCXI.
Is 1211 divisible by 3?
No. Its digits add up to 5, which is not a multiple of 3.
What is special about the number 1211?
1211 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 7 × 173, the product of two primes.