The number 18900
18900 is a composite number with 72 divisors. Its prime factorisation is × × × 7. Divisors (72): 1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 14, 15, 18, 20, 21, 25 … 18900.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18900: a Harshad number: divisible by its digit sum 18.
- 2
18900 is composite. Its prime factorisation is
- 3
The divisors add up to 69440; without 18900 itself that is 50540, so 18900 is abundant (50540 is more than 18900). Euler's totient φ(18900) = 4320 numbers up to 18900 share no factor with it.
- 4
The digits of 18900 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 61 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18900 = 2^{2} \times 3^{3} \times 5^{2} \times 7 \]18900 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 72 |
| Sum of divisors | 69440 |
| Euler totient φ(n) | 4320 |
| Square | 357210000 |
| Cube | 6751269000000 |
| Square root | 137.477271 (= 30√21) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 61 |
| Scientific notation | 1.89 × |
18900 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand nine hundred |
| Binary (base 2) | 100100111010100 |
| Octal (base 8) | 44724 |
| Hexadecimal (base 16) | 49D4 |
| Base 3 | 221221000 |
| As time | 18900 seconds = 5 h 15 min 0 s |
Is 18900 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (18900 ÷ 2 = 9450) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (18900 ÷ 3 = 6300) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (18900 ÷ 4 = 4725) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (18900 ÷ 5 = 3780) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (18900 ÷ 6 = 3150) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (18900 ÷ 7 = 2700) | 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 (18900 ÷ 9 = 2100) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (18900 ÷ 10 = 1890) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (18900 ÷ 12 = 1575) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18900 a prime number?
No. 18900 = × × × 7, so it is divisible by 2.
What are the factors of 18900?
1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 14, 15, 18, 20, 21, 25, 27, 28, 30, 35, 36, 42, 45, 50, 54, 60, 63, 70, 75, 84, 90, 100, 105, 108, 126, 135, 140, 150, 175, 180, 189, 210, 225, 252, 270, 300, 315, 350, 378, 420, 450, 525, 540, 630, 675, 700, 756, 900, 945, 1050, 1260, 1350, 1575, 1890, 2100, 2700, 3150, 3780, 4725, 6300, 9450, 18900.
What is 18900 in binary?
100100111010100 (hexadecimal 49D4, octal 44724).
What is the square root of 18900?
About 137.4773, exactly 30√21.
Is 18900 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 18900?
18900 is a Harshad number: divisible by its digit sum 18.