The number 724
724 is a composite number with 6 divisors. Its prime factorisation is × 181. Divisors (6): 1, 2, 4, 181, 362, 724.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
724 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
724 is composite. Its prime factorisation is
- 3
The divisors add up to 1274; without 724 itself that is 550, so 724 is deficient (550 is less than 724). Euler's totient φ(724) = 360 numbers up to 724 share no factor with it.
- 4
The digits of 724 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 20 steps to reach 1.
LaTeX source of the formulas on this page
\[ 724 = 2^{2} \times 181 \]724 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 1274 |
| Euler totient φ(n) | 360 |
| Square | 524176 |
| Cube | 379503424 |
| Square root | 26.907248 (= 2√181) |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 20 |
| Scientific notation | 7.24 × |
724 in other forms
| Form | Value |
|---|---|
| In words | seven hundred and twenty-four |
| Roman numerals | DCCXXIV |
| Binary (base 2) | 1011010100 |
| Octal (base 8) | 1324 |
| Hexadecimal (base 16) | 2D4 |
| Base 3 | 222211 |
| As time | 724 seconds = 12 min 4 s |
Is 724 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (724 ÷ 2 = 362) | 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 | Yes (724 ÷ 4 = 181) | 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 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 4) | 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 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 724 a prime number?
No. 724 = × 181, so it is divisible by 2.
What are the factors of 724?
1, 2, 4, 181, 362, 724.
What is 724 in binary?
1011010100 (hexadecimal 2D4, octal 1324).
What is the square root of 724?
About 26.9072, exactly 2√181.
What is 724 in Roman numerals?
DCCXXIV.
Is 724 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 724?
It is a composite number with 6 divisors.