The number 6921
6921 is a composite number with 6 divisors. Its prime factorisation is × 769. Divisors (6): 1, 3, 9, 769, 2307, 6921.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
6921 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
6921 is composite. Its prime factorisation is
- 3
The divisors add up to 10010; without 6921 itself that is 3089, so 6921 is deficient (3089 is less than 6921). Euler's totient φ(6921) = 4608 numbers up to 6921 share no factor with it.
- 4
The digits of 6921 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 75 steps to reach 1.
LaTeX source of the formulas on this page
\[ 6921 = 3^{2} \times 769 \]6921 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 10010 |
| Euler totient φ(n) | 4608 |
| Square | 47900241 |
| Cube | 331517567961 |
| Square root | 83.192548 (= 3√769) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 75 |
| Scientific notation | 6.921 × |
6921 in other forms
| Form | Value |
|---|---|
| In words | six thousand nine hundred and twenty-one |
| Binary (base 2) | 1101100001001 |
| Octal (base 8) | 15411 |
| Hexadecimal (base 16) | 1B09 |
| Base 3 | 100111100 |
| As time | 6921 seconds = 1 h 55 min 21 s |
Is 6921 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 (6921 ÷ 3 = 2307) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | 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 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (6921 ÷ 9 = 769) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | 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 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 6921 a prime number?
No. 6921 = × 769, so it is divisible by 3.
What are the factors of 6921?
1, 3, 9, 769, 2307, 6921.
What is 6921 in binary?
1101100001001 (hexadecimal 1B09, octal 15411).
What is the square root of 6921?
About 83.1925, exactly 3√769.
Is 6921 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 6921?
It is a composite number with 6 divisors.