The number 1121
1121 is a composite number with 4 divisors. Its prime factorisation is 19 × 59. Divisors (4): 1, 19, 59, 1121.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1121: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 19 × 59, the product of two primes.
- 2
1121 is composite. Its prime factorisation is
- 3
The divisors add up to 1200; without 1121 itself that is 79, so 1121 is deficient (79 is less than 1121). Euler's totient φ(1121) = 1044 numbers up to 1121 share no factor with it.
- 4
The digits of 1121 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 44 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1121 = 19 \times 59 \]
1121 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1200 |
| Euler totient φ(n) | 1044 |
| Square | 1256641 |
| Cube | 1408694561 |
| Square root | 33.481338 |
| Digit sum / digital root | 5 / 5 |
| Collatz steps to 1 | 44 |
| Scientific notation | 1.121 × |
1121 in other forms
| Form | Value |
|---|---|
| In words | one thousand one hundred and twenty-one |
| Roman numerals | MCXXI |
| Binary (base 2) | 10001100001 |
| Octal (base 8) | 2141 |
| Hexadecimal (base 16) | 461 |
| Base 3 | 1112112 |
| As time | 1121 seconds = 18 min 41 s |
Is 1121 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 1) | 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 | 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 1) | 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 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1121 a prime number?
No. 1121 = 19 × 59, so it is divisible by 19.
What are the factors of 1121?
1, 19, 59, 1121.
What is 1121 in binary?
10001100001 (hexadecimal 461, octal 2141).
What is the square root of 1121?
About 33.4813.
What is 1121 in Roman numerals?
MCXXI.
Is 1121 divisible by 3?
No. Its digits add up to 5, which is not a multiple of 3.
What is special about the number 1121?
1121 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 19 × 59, the product of two primes.