The number 1255
1255 is a composite number with 4 divisors. Its prime factorisation is 5 × 251. Divisors (4): 1, 5, 251, 1255.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1255: a semiprime: 5 × 251, the product of two primes.
- 2
1255 is composite. Its prime factorisation is
- 3
The divisors add up to 1512; without 1255 itself that is 257, so 1255 is deficient (257 is less than 1255). Euler's totient φ(1255) = 1000 numbers up to 1255 share no factor with it.
- 4
The digits of 1255 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 88 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1255 = 5 \times 251 \]
1255 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1512 |
| Euler totient φ(n) | 1000 |
| Square | 1575025 |
| Cube | 1976656375 |
| Square root | 35.425979 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 88 |
| Scientific notation | 1.255 × |
1255 in other forms
| Form | Value |
|---|---|
| In words | one thousand two hundred and fifty-five |
| Roman numerals | MCCLV |
| Binary (base 2) | 10011100111 |
| Octal (base 8) | 2347 |
| Hexadecimal (base 16) | 4E7 |
| Base 3 | 1201111 |
| As time | 1255 seconds = 20 min 55 s |
Is 1255 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 | Yes (1255 ÷ 5 = 251) | 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 2) | 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 5) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1255 a prime number?
No. 1255 = 5 × 251, so it is divisible by 5.
What are the factors of 1255?
1, 5, 251, 1255.
What is 1255 in binary?
10011100111 (hexadecimal 4E7, octal 2347).
What is the square root of 1255?
About 35.4260.
What is 1255 in Roman numerals?
MCCLV.
Is 1255 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 1255?
1255 is a semiprime: 5 × 251, the product of two primes.