The number 1111
1111 is a palindrome: it reads 1111 backwards too. Its prime factorisation is 11 × 101. Divisors (4): 1, 11, 101, 1111.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1111: a palindrome: it reads 1111 backwards too; a semiprime: 11 × 101, the product of two primes.
- 2
1111 is composite. Its prime factorisation is
- 3
The divisors add up to 1224; without 1111 itself that is 113, so 1111 is deficient (113 is less than 1111). Euler's totient φ(1111) = 1000 numbers up to 1111 share no factor with it.
- 4
The digits of 1111 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 31 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1111 = 11 \times 101 \]
1111 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1224 |
| Euler totient φ(n) | 1000 |
| Square | 1234321 |
| Cube | 1371330631 |
| Square root | 33.331667 |
| Digit sum / digital root | 4 / 4 |
| Collatz steps to 1 | 31 |
| Scientific notation | 1.111 × |
1111 in other forms
| Form | Value |
|---|---|
| In words | one thousand one hundred and eleven |
| Roman numerals | MCXI |
| Binary (base 2) | 10001010111 |
| Octal (base 8) | 2127 |
| Hexadecimal (base 16) | 457 |
| Base 3 | 1112011 |
| As time | 1111 seconds = 18 min 31 s |
Is 1111 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 5) | 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 7) | 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 | Yes (1111 ÷ 11 = 101) | 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 1111 a prime number?
No. 1111 = 11 × 101, so it is divisible by 11.
What are the factors of 1111?
1, 11, 101, 1111.
What is 1111 in binary?
10001010111 (hexadecimal 457, octal 2127).
What is the square root of 1111?
About 33.3317.
What is 1111 in Roman numerals?
MCXI.
Is 1111 divisible by 3?
No. Its digits add up to 4, which is not a multiple of 3.
What is special about the number 1111?
1111 is a palindrome: it reads 1111 backwards too; a semiprime: 11 × 101, the product of two primes.