The number 16640
16640 is a composite number with 36 divisors. Its prime factorisation is × 5 × 13. Divisors (36): 1, 2, 4, 5, 8, 10, 13, 16, 20, 26, 32, 40, 52, 64, 65, 80 … 16640.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
16640 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
16640 is composite. Its prime factorisation is
- 3
The divisors add up to 42924; without 16640 itself that is 26284, so 16640 is abundant (26284 is more than 16640). Euler's totient φ(16640) = 6144 numbers up to 16640 share no factor with it.
- 4
The digits of 16640 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 35 steps to reach 1.
LaTeX source of the formulas on this page
\[ 16640 = 2^{8} \times 5 \times 13 \]16640 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 36 |
| Sum of divisors | 42924 |
| Euler totient φ(n) | 6144 |
| Square | 276889600 |
| Cube | 4607442944000 |
| Square root | 128.996124 (= 16√65) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 35 |
| Scientific notation | 1.664 × |
16640 in other forms
| Form | Value |
|---|---|
| In words | sixteen thousand six hundred and forty |
| Binary (base 2) | 100000100000000 |
| Octal (base 8) | 40400 |
| Hexadecimal (base 16) | 4100 |
| Base 3 | 211211022 |
| As time | 16640 seconds = 4 h 37 min 20 s |
Is 16640 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (16640 ÷ 2 = 8320) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (16640 ÷ 4 = 4160) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (16640 ÷ 5 = 3328) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | 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 | Yes (16640 ÷ 8 = 2080) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (16640 ÷ 10 = 1664) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 16640 a prime number?
No. 16640 = × 5 × 13, so it is divisible by 2.
What are the factors of 16640?
1, 2, 4, 5, 8, 10, 13, 16, 20, 26, 32, 40, 52, 64, 65, 80, 104, 128, 130, 160, 208, 256, 260, 320, 416, 520, 640, 832, 1040, 1280, 1664, 2080, 3328, 4160, 8320, 16640.
What is 16640 in binary?
100000100000000 (hexadecimal 4100, octal 40400).
What is the square root of 16640?
About 128.9961, exactly 16√65.
Is 16640 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 16640?
It is a composite number with 36 divisors.