The number 511
511 is a binary palindrome (111111111). Its prime factorisation is 7 × 73. Divisors (4): 1, 7, 73, 511.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 511: a binary palindrome (111111111); a Harshad number: divisible by its digit sum 7; a semiprime: 7 × 73, the product of two primes.
- 2
511 is composite. Its prime factorisation is
- 3
The divisors add up to 592; without 511 itself that is 81, so 511 is deficient (81 is less than 511). Euler's totient φ(511) = 432 numbers up to 511 share no factor with it.
- 4
The digits of 511 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 61 steps to reach 1.
LaTeX source of the formulas on this page
\[ 511 = 7 \times 73 \]
511 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 592 |
| Euler totient φ(n) | 432 |
| Square | 261121 |
| Cube | 133432831 |
| Square root | 22.605309 |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 61 |
| Scientific notation | 5.11 × |
511 in other forms
| Form | Value |
|---|---|
| In words | five hundred and eleven |
| Roman numerals | DXI |
| Binary (base 2) | 111111111 |
| Octal (base 8) | 777 |
| Hexadecimal (base 16) | 1FF |
| Base 3 | 200221 |
| As time | 511 seconds = 8 min 31 s |
Is 511 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 | Yes (511 ÷ 7 = 73) | 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 7) | 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 5) | 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 511 a prime number?
No. 511 = 7 × 73, so it is divisible by 7.
What are the factors of 511?
1, 7, 73, 511.
What is 511 in binary?
111111111 (hexadecimal 1FF, octal 777).
What is the square root of 511?
About 22.6053.
What is 511 in Roman numerals?
DXI.
Is 511 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 511?
511 is a binary palindrome (111111111); a Harshad number: divisible by its digit sum 7; a semiprime: 7 × 73, the product of two primes.