The number 18820
18820 is a composite number with 12 divisors. Its prime factorisation is × 5 × 941. Divisors (12): 1, 2, 4, 5, 10, 20, 941, 1882, 3764, 4705, 9410, 18820.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18820: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
18820 is composite. Its prime factorisation is
- 3
The divisors add up to 39564; without 18820 itself that is 20744, so 18820 is abundant (20744 is more than 18820). Euler's totient φ(18820) = 7520 numbers up to 18820 share no factor with it.
- 4
The digits of 18820 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 61 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18820 = 2^{2} \times 5 \times 941 \]18820 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 39564 |
| Euler totient φ(n) | 7520 |
| Square | 354192400 |
| Cube | 6665900968000 |
| Square root | 137.186005 (= 2√4705) |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 61 |
| Scientific notation | 1.882 × |
18820 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand eight hundred and twenty |
| Binary (base 2) | 100100110000100 |
| Octal (base 8) | 44604 |
| Hexadecimal (base 16) | 4984 |
| Base 3 | 221211001 |
| As time | 18820 seconds = 5 h 13 min 40 s |
Is 18820 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (18820 ÷ 2 = 9410) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (18820 ÷ 4 = 4705) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (18820 ÷ 5 = 3764) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (18820 ÷ 10 = 1882) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18820 a prime number?
No. 18820 = × 5 × 941, so it is divisible by 2.
What are the factors of 18820?
1, 2, 4, 5, 10, 20, 941, 1882, 3764, 4705, 9410, 18820.
What is 18820 in binary?
100100110000100 (hexadecimal 4984, octal 44604).
What is the square root of 18820?
About 137.1860, exactly 2√4705.
Is 18820 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 18820?
18820 is a happy number: repeatedly adding the squares of its digits reaches 1.