The number 1275
1275 is a triangular number: 1 + 2 + … + 50 = 1275. Its prime factorisation is 3 × × 17. Divisors (12): 1, 3, 5, 15, 17, 25, 51, 75, 85, 255, 425, 1275.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1275: a triangular number: 1 + 2 + … + 50 = 1275; a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 15.
- 2
1275 is composite. Its prime factorisation is
- 3
The divisors add up to 2232; without 1275 itself that is 957, so 1275 is deficient (957 is less than 1275). Euler's totient φ(1275) = 640 numbers up to 1275 share no factor with it.
- 4
The digits of 1275 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 83 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1275 = 3 \times 5^{2} \times 17 \]1275 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 2232 |
| Euler totient φ(n) | 640 |
| Square | 1625625 |
| Cube | 2072671875 |
| Square root | 35.707142 (= 5√51) |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 83 |
| Scientific notation | 1.275 × |
1275 in other forms
| Form | Value |
|---|---|
| In words | one thousand two hundred and seventy-five |
| Roman numerals | MCCLXXV |
| Binary (base 2) | 10011111011 |
| Octal (base 8) | 2373 |
| Hexadecimal (base 16) | 4FB |
| Base 3 | 1202020 |
| As time | 1275 seconds = 21 min 15 s |
Is 1275 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 | Yes (1275 ÷ 3 = 425) | 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 | Yes (1275 ÷ 5 = 255) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | 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 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | 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 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1275 a prime number?
No. 1275 = 3 × × 17, so it is divisible by 3.
What are the factors of 1275?
1, 3, 5, 15, 17, 25, 51, 75, 85, 255, 425, 1275.
What is 1275 in binary?
10011111011 (hexadecimal 4FB, octal 2373).
What is the square root of 1275?
About 35.7071, exactly 5√51.
What is 1275 in Roman numerals?
MCCLXXV.
Is 1275 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 1275?
1275 is a triangular number: 1 + 2 + … + 50 = 1275; a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 15.