The number 20900
20900 is a composite number with 36 divisors. Its prime factorisation is × × 11 × 19. Divisors (36): 1, 2, 4, 5, 10, 11, 19, 20, 22, 25, 38, 44, 50, 55, 76, 95 … 20900.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20900: a Harshad number: divisible by its digit sum 11.
- 2
20900 is composite. Its prime factorisation is
- 3
The divisors add up to 52080; without 20900 itself that is 31180, so 20900 is abundant (31180 is more than 20900). Euler's totient φ(20900) = 7200 numbers up to 20900 share no factor with it.
- 4
The digits of 20900 add up to 11, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 87 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20900 = 2^{2} \times 5^{2} \times 11 \times 19 \]20900 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 36 |
| Sum of divisors | 52080 |
| Euler totient φ(n) | 7200 |
| Square | 436810000 |
| Cube | 9129329000000 |
| Square root | 144.568323 (= 10√209) |
| Digit sum / digital root | 11 / 2 |
| Collatz steps to 1 | 87 |
| Scientific notation | 2.09 × |
20900 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand nine hundred |
| Binary (base 2) | 101000110100100 |
| Octal (base 8) | 50644 |
| Hexadecimal (base 16) | 51A4 |
| Base 3 | 1001200002 |
| As time | 20900 seconds = 5 h 48 min 20 s |
Is 20900 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (20900 ÷ 2 = 10450) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (20900 ÷ 4 = 5225) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (20900 ÷ 5 = 4180) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (20900 ÷ 10 = 2090) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (20900 ÷ 11 = 1900) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20900 a prime number?
No. 20900 = × × 11 × 19, so it is divisible by 2.
What are the factors of 20900?
1, 2, 4, 5, 10, 11, 19, 20, 22, 25, 38, 44, 50, 55, 76, 95, 100, 110, 190, 209, 220, 275, 380, 418, 475, 550, 836, 950, 1045, 1100, 1900, 2090, 4180, 5225, 10450, 20900.
What is 20900 in binary?
101000110100100 (hexadecimal 51A4, octal 50644).
What is the square root of 20900?
About 144.5683, exactly 10√209.
Is 20900 divisible by 3?
No. Its digits add up to 11, which is not a multiple of 3.
What is special about the number 20900?
20900 is a Harshad number: divisible by its digit sum 11.