The number 20787
20787 is a composite number with 12 divisors. Its prime factorisation is 3 × × 41. Divisors (12): 1, 3, 13, 39, 41, 123, 169, 507, 533, 1599, 6929, 20787.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
20787 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
20787 is composite. Its prime factorisation is
- 3
The divisors add up to 30744; without 20787 itself that is 9957, so 20787 is deficient (9957 is less than 20787). Euler's totient φ(20787) = 12480 numbers up to 20787 share no factor with it.
- 4
The digits of 20787 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 149 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20787 = 3 \times 13^{2} \times 41 \]20787 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 30744 |
| Euler totient φ(n) | 12480 |
| Square | 432099369 |
| Cube | 8982049583403 |
| Square root | 144.176975 (= 13√123) |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 149 |
| Scientific notation | 2.0787 × |
20787 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand seven hundred and eighty-seven |
| Binary (base 2) | 101000100110011 |
| Octal (base 8) | 50463 |
| Hexadecimal (base 16) | 5133 |
| Base 3 | 1001111220 |
| As time | 20787 seconds = 5 h 46 min 27 s |
Is 20787 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 (20787 ÷ 3 = 6929) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | 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 | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 7) | 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 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20787 a prime number?
No. 20787 = 3 × × 41, so it is divisible by 3.
What are the factors of 20787?
1, 3, 13, 39, 41, 123, 169, 507, 533, 1599, 6929, 20787.
What is 20787 in binary?
101000100110011 (hexadecimal 5133, octal 50463).
What is the square root of 20787?
About 144.1770, exactly 13√123.
Is 20787 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 20787?
It is a composite number with 12 divisors.