The number 18180
18180 is a composite number with 36 divisors. Its prime factorisation is × × 5 × 101. Divisors (36): 1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 30, 36, 45, 60 … 18180.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18180: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.
- 2
18180 is composite. Its prime factorisation is
- 3
The divisors add up to 55692; without 18180 itself that is 37512, so 18180 is abundant (37512 is more than 18180). Euler's totient φ(18180) = 4800 numbers up to 18180 share no factor with it.
- 4
The digits of 18180 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 141 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18180 = 2^{2} \times 3^{2} \times 5 \times 101 \]18180 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 36 |
| Sum of divisors | 55692 |
| Euler totient φ(n) | 4800 |
| Square | 330512400 |
| Cube | 6008715432000 |
| Square root | 134.833230 (= 6√505) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 141 |
| Scientific notation | 1.818 × |
18180 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand one hundred and eighty |
| Binary (base 2) | 100011100000100 |
| Octal (base 8) | 43404 |
| Hexadecimal (base 16) | 4704 |
| Base 3 | 220221100 |
| As time | 18180 seconds = 5 h 3 min 0 s |
Is 18180 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (18180 ÷ 2 = 9090) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (18180 ÷ 3 = 6060) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (18180 ÷ 4 = 4545) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (18180 ÷ 5 = 3636) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (18180 ÷ 6 = 3030) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 | Yes (18180 ÷ 9 = 2020) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (18180 ÷ 10 = 1818) | 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 | Yes (18180 ÷ 12 = 1515) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18180 a prime number?
No. 18180 = × × 5 × 101, so it is divisible by 2.
What are the factors of 18180?
1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 30, 36, 45, 60, 90, 101, 180, 202, 303, 404, 505, 606, 909, 1010, 1212, 1515, 1818, 2020, 3030, 3636, 4545, 6060, 9090, 18180.
What is 18180 in binary?
100011100000100 (hexadecimal 4704, octal 43404).
What is the square root of 18180?
About 134.8332, exactly 6√505.
Is 18180 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 18180?
18180 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.