The number 16521
16521 is a composite number with 4 divisors. Its prime factorisation is 3 × 5507. Divisors (4): 1, 3, 5507, 16521.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 16521: a semiprime: 3 × 5507, the product of two primes.
- 2
16521 is composite. Its prime factorisation is
- 3
The divisors add up to 22032; without 16521 itself that is 5511, so 16521 is deficient (5511 is less than 16521). Euler's totient φ(16521) = 11012 numbers up to 16521 share no factor with it.
- 4
The digits of 16521 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 66 steps to reach 1.
LaTeX source of the formulas on this page
\[ 16521 = 3 \times 5507 \]
16521 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 22032 |
| Euler totient φ(n) | 11012 |
| Square | 272943441 |
| Cube | 4509298588761 |
| Square root | 128.534042 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 66 |
| Scientific notation | 1.6521 × |
16521 in other forms
| Form | Value |
|---|---|
| In words | sixteen thousand five hundred and twenty-one |
| Binary (base 2) | 100000010001001 |
| Octal (base 8) | 40211 |
| Hexadecimal (base 16) | 4089 |
| Base 3 | 211122220 |
| As time | 16521 seconds = 4 h 35 min 21 s |
Is 16521 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 (16521 ÷ 3 = 5507) | 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 1) | 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 | No (remainder 6) | 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 10) | 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 16521 a prime number?
No. 16521 = 3 × 5507, so it is divisible by 3.
What are the factors of 16521?
1, 3, 5507, 16521.
What is 16521 in binary?
100000010001001 (hexadecimal 4089, octal 40211).
What is the square root of 16521?
About 128.5340.
Is 16521 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 16521?
16521 is a semiprime: 3 × 5507, the product of two primes.