The number 7209
7209 is a composite number with 10 divisors. Its prime factorisation is × 89. Divisors (10): 1, 3, 9, 27, 81, 89, 267, 801, 2403, 7209.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
7209 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
7209 is composite. Its prime factorisation is
- 3
The divisors add up to 10890; without 7209 itself that is 3681, so 7209 is deficient (3681 is less than 7209). Euler's totient φ(7209) = 4752 numbers up to 7209 share no factor with it.
- 4
The digits of 7209 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 70 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7209 = 3^{4} \times 89 \]7209 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 10 |
| Sum of divisors | 10890 |
| Euler totient φ(n) | 4752 |
| Square | 51969681 |
| Cube | 374649430329 |
| Square root | 84.905830 (= 9√89) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 70 |
| Scientific notation | 7.209 × |
7209 in other forms
| Form | Value |
|---|---|
| In words | seven thousand two hundred and nine |
| Binary (base 2) | 1110000101001 |
| Octal (base 8) | 16051 |
| Hexadecimal (base 16) | 1C29 |
| Base 3 | 100220000 |
| As time | 7209 seconds = 2 h 0 min 9 s |
Is 7209 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 (7209 ÷ 3 = 2403) | 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 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (7209 ÷ 9 = 801) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 7209 a prime number?
No. 7209 = × 89, so it is divisible by 3.
What are the factors of 7209?
1, 3, 9, 27, 81, 89, 267, 801, 2403, 7209.
What is 7209 in binary?
1110000101001 (hexadecimal 1C29, octal 16051).
What is the square root of 7209?
About 84.9058, exactly 9√89.
Is 7209 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 7209?
It is a composite number with 10 divisors.