The number 16491
16491 is a composite number with 8 divisors. Its prime factorisation is 3 × 23 × 239. Divisors (8): 1, 3, 23, 69, 239, 717, 5497, 16491.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
16491 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
16491 is composite. Its prime factorisation is
- 3
The divisors add up to 23040; without 16491 itself that is 6549, so 16491 is deficient (6549 is less than 16491). Euler's totient φ(16491) = 10472 numbers up to 16491 share no factor with it.
- 4
The digits of 16491 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 66 steps to reach 1.
LaTeX source of the formulas on this page
\[ 16491 = 3 \times 23 \times 239 \]
16491 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 23040 |
| Euler totient φ(n) | 10472 |
| Square | 271953081 |
| Cube | 4484778258771 |
| Square root | 128.417289 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 66 |
| Scientific notation | 1.6491 × |
16491 in other forms
| Form | Value |
|---|---|
| In words | sixteen thousand four hundred and ninety-one |
| Binary (base 2) | 100000001101011 |
| Octal (base 8) | 40153 |
| Hexadecimal (base 16) | 406B |
| Base 3 | 211121210 |
| As time | 16491 seconds = 4 h 34 min 51 s |
Is 16491 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 (16491 ÷ 3 = 5497) | 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 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 6) | 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 3) | 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 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 16491 a prime number?
No. 16491 = 3 × 23 × 239, so it is divisible by 3.
What are the factors of 16491?
1, 3, 23, 69, 239, 717, 5497, 16491.
What is 16491 in binary?
100000001101011 (hexadecimal 406B, octal 40153).
What is the square root of 16491?
About 128.4173.
Is 16491 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 16491?
It is a composite number with 8 divisors.