The number 249
249 is a composite number with 4 divisors. Its prime factorisation is 3 × 83. Divisors (4): 1, 3, 83, 249.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 249: a semiprime: 3 × 83, the product of two primes.
- 2
249 is composite. Its prime factorisation is
- 3
The divisors add up to 336; without 249 itself that is 87, so 249 is deficient (87 is less than 249). Euler's totient φ(249) = 164 numbers up to 249 share no factor with it.
- 4
The digits of 249 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 47 steps to reach 1.
LaTeX source of the formulas on this page
\[ 249 = 3 \times 83 \]
249 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 336 |
| Euler totient φ(n) | 164 |
| Square | 62001 |
| Cube | 15438249 |
| Square root | 15.779734 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 47 |
| Scientific notation | 2.49 × |
249 in other forms
| Form | Value |
|---|---|
| In words | two hundred and forty-nine |
| Roman numerals | CCXLIX |
| Binary (base 2) | 11111001 |
| Octal (base 8) | 371 |
| Hexadecimal (base 16) | F9 |
| Base 3 | 100020 |
| As time | 249 seconds = 4 min 9 s |
Is 249 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 (249 ÷ 3 = 83) | 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 4) | 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 4) | 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 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 249 a prime number?
No. 249 = 3 × 83, so it is divisible by 3.
What are the factors of 249?
1, 3, 83, 249.
What is 249 in binary?
11111001 (hexadecimal F9, octal 371).
What is the square root of 249?
About 15.7797.
What is 249 in Roman numerals?
CCXLIX.
Is 249 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 249?
249 is a semiprime: 3 × 83, the product of two primes.