The number 279
279 is a composite number with 6 divisors. Its prime factorisation is × 31. Divisors (6): 1, 3, 9, 31, 93, 279.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
279 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
279 is composite. Its prime factorisation is
- 3
The divisors add up to 416; without 279 itself that is 137, so 279 is deficient (137 is less than 279). Euler's totient φ(279) = 180 numbers up to 279 share no factor with it.
- 4
The digits of 279 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 42 steps to reach 1.
LaTeX source of the formulas on this page
\[ 279 = 3^{2} \times 31 \]279 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 416 |
| Euler totient φ(n) | 180 |
| Square | 77841 |
| Cube | 21717639 |
| Square root | 16.703293 (= 3√31) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 42 |
| Scientific notation | 2.79 × |
279 in other forms
| Form | Value |
|---|---|
| In words | two hundred and seventy-nine |
| Roman numerals | CCLXXIX |
| Binary (base 2) | 100010111 |
| Octal (base 8) | 427 |
| Hexadecimal (base 16) | 117 |
| Base 3 | 101100 |
| As time | 279 seconds = 4 min 39 s |
Is 279 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 (279 ÷ 3 = 93) | 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 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 6) | 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 | Yes (279 ÷ 9 = 31) | 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 4) | 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 279 a prime number?
No. 279 = × 31, so it is divisible by 3.
What are the factors of 279?
1, 3, 9, 31, 93, 279.
What is 279 in binary?
100010111 (hexadecimal 117, octal 427).
What is the square root of 279?
About 16.7033, exactly 3√31.
What is 279 in Roman numerals?
CCLXXIX.
Is 279 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 279?
It is a composite number with 6 divisors.