The number 55209
55209 is a composite number with 16 divisors. Its prime factorisation is 3 × 7 × 11 × 239. Divisors (16): 1, 3, 7, 11, 21, 33, 77, 231, 239, 717, 1673, 2629, 5019, 7887, 18403, 55209.
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How to work it out
- 1
What is special about 55209: a Harshad number: divisible by its digit sum 21.
- 2
55209 is composite. Its prime factorisation is
- 3
The divisors add up to 92160; without 55209 itself that is 36951, so 55209 is deficient (36951 is less than 55209). Euler's totient φ(55209) = 28560 numbers up to 55209 share no factor with it.
- 4
The digits of 55209 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 228 steps to reach 1.
LaTeX source of the formulas on this page
\[ 55209 = 3 \times 7 \times 11 \times 239 \]
55209 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 92160 |
| Euler totient φ(n) | 28560 |
| Square | 3048033681 |
| Cube | 168278891494329 |
| Square root | 234.965955 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 228 |
| Scientific notation | 5.5209 × |
55209 in other forms
| Form | Value |
|---|---|
| In words | fifty-five thousand two hundred and nine |
| Binary (base 2) | 1101011110101001 |
| Octal (base 8) | 153651 |
| Hexadecimal (base 16) | D7A9 |
| Base 3 | 2210201210 |
| As time | 55209 seconds = 15 h 20 min 9 s |
Is 55209 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 (55209 ÷ 3 = 18403) | 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 | Yes (55209 ÷ 7 = 7887) | 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 3) | 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 | Yes (55209 ÷ 11 = 5019) | 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 55209 a prime number?
No. 55209 = 3 × 7 × 11 × 239, so it is divisible by 3.
What are the factors of 55209?
1, 3, 7, 11, 21, 33, 77, 231, 239, 717, 1673, 2629, 5019, 7887, 18403, 55209.
What is 55209 in binary?
1101011110101001 (hexadecimal D7A9, octal 153651).
What is the square root of 55209?
About 234.9660.
Is 55209 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 55209?
55209 is a Harshad number: divisible by its digit sum 21.