The number 16221
16221 is a composite number with 4 divisors. Its prime factorisation is 3 × 5407. Divisors (4): 1, 3, 5407, 16221.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 16221: a semiprime: 3 × 5407, the product of two primes.
- 2
16221 is composite. Its prime factorisation is
- 3
The divisors add up to 21632; without 16221 itself that is 5411, so 16221 is deficient (5411 is less than 16221). Euler's totient φ(16221) = 10812 numbers up to 16221 share no factor with it.
- 4
The digits of 16221 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 159 steps to reach 1.
LaTeX source of the formulas on this page
\[ 16221 = 3 \times 5407 \]
16221 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 21632 |
| Euler totient φ(n) | 10812 |
| Square | 263120841 |
| Cube | 4268083161861 |
| Square root | 127.361690 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 159 |
| Scientific notation | 1.6221 × |
16221 in other forms
| Form | Value |
|---|---|
| In words | sixteen thousand two hundred and twenty-one |
| Binary (base 2) | 11111101011101 |
| Octal (base 8) | 37535 |
| Hexadecimal (base 16) | 3F5D |
| Base 3 | 211020210 |
| As time | 16221 seconds = 4 h 30 min 21 s |
Is 16221 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 (16221 ÷ 3 = 5407) | 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 2) | 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 5) | 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 7) | 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 16221 a prime number?
No. 16221 = 3 × 5407, so it is divisible by 3.
What are the factors of 16221?
1, 3, 5407, 16221.
What is 16221 in binary?
11111101011101 (hexadecimal 3F5D, octal 37535).
What is the square root of 16221?
About 127.3617.
Is 16221 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 16221?
16221 is a semiprime: 3 × 5407, the product of two primes.