The number 16621
16621 is a composite number with 4 divisors. Its prime factorisation is 11 × 1511. Divisors (4): 1, 11, 1511, 16621.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 16621: a semiprime: 11 × 1511, the product of two primes.
- 2
16621 is composite. Its prime factorisation is
- 3
The divisors add up to 18144; without 16621 itself that is 1523, so 16621 is deficient (1523 is less than 16621). Euler's totient φ(16621) = 15100 numbers up to 16621 share no factor with it.
- 4
The digits of 16621 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 66 steps to reach 1.
LaTeX source of the formulas on this page
\[ 16621 = 11 \times 1511 \]
16621 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 18144 |
| Euler totient φ(n) | 15100 |
| Square | 276257641 |
| Cube | 4591678251061 |
| Square root | 128.922457 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 66 |
| Scientific notation | 1.6621 × |
16621 in other forms
| Form | Value |
|---|---|
| In words | sixteen thousand six hundred and twenty-one |
| Binary (base 2) | 100000011101101 |
| Octal (base 8) | 40355 |
| Hexadecimal (base 16) | 40ED |
| Base 3 | 211210121 |
| As time | 16621 seconds = 4 h 37 min 1 s |
Is 16621 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 | No (remainder 1) | 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 7) | 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 | Yes (16621 ÷ 11 = 1511) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 16621 a prime number?
No. 16621 = 11 × 1511, so it is divisible by 11.
What are the factors of 16621?
1, 11, 1511, 16621.
What is 16621 in binary?
100000011101101 (hexadecimal 40ED, octal 40355).
What is the square root of 16621?
About 128.9225.
Is 16621 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 16621?
16621 is a semiprime: 11 × 1511, the product of two primes.