The number 7389
7389 is a composite number with 6 divisors. Its prime factorisation is × 821. Divisors (6): 1, 3, 9, 821, 2463, 7389.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 7389: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
7389 is composite. Its prime factorisation is
- 3
The divisors add up to 10686; without 7389 itself that is 3297, so 7389 is deficient (3297 is less than 7389). Euler's totient φ(7389) = 4920 numbers up to 7389 share no factor with it.
- 4
The digits of 7389 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 70 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7389 = 3^{2} \times 821 \]7389 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 10686 |
| Euler totient φ(n) | 4920 |
| Square | 54597321 |
| Cube | 403419604869 |
| Square root | 85.959293 (= 3√821) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 70 |
| Scientific notation | 7.389 × |
7389 in other forms
| Form | Value |
|---|---|
| In words | seven thousand three hundred and eighty-nine |
| Binary (base 2) | 1110011011101 |
| Octal (base 8) | 16335 |
| Hexadecimal (base 16) | 1CDD |
| Base 3 | 101010200 |
| As time | 7389 seconds = 2 h 3 min 9 s |
Is 7389 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 (7389 ÷ 3 = 2463) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (7389 ÷ 9 = 821) | 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 8) | 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 7389 a prime number?
No. 7389 = × 821, so it is divisible by 3.
What are the factors of 7389?
1, 3, 9, 821, 2463, 7389.
What is 7389 in binary?
1110011011101 (hexadecimal 1CDD, octal 16335).
What is the square root of 7389?
About 85.9593, exactly 3√821.
Is 7389 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 7389?
7389 is a happy number: repeatedly adding the squares of its digits reaches 1.