The number 21608
21608 is a composite number with 16 divisors. Its prime factorisation is × 37 × 73. Divisors (16): 1, 2, 4, 8, 37, 73, 74, 146, 148, 292, 296, 584, 2701, 5402, 10804, 21608.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21608 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21608 is composite. Its prime factorisation is
- 3
The divisors add up to 42180; without 21608 itself that is 20572, so 21608 is deficient (20572 is less than 21608). Euler's totient φ(21608) = 10368 numbers up to 21608 share no factor with it.
- 4
The digits of 21608 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 118 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21608 = 2^{3} \times 37 \times 73 \]21608 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 42180 |
| Euler totient φ(n) | 10368 |
| Square | 466905664 |
| Cube | 10088897587712 |
| Square root | 146.996599 (= 2√5402) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 118 |
| Scientific notation | 2.1608 × |
21608 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand six hundred and eight |
| Binary (base 2) | 101010001101000 |
| Octal (base 8) | 52150 |
| Hexadecimal (base 16) | 5468 |
| Base 3 | 1002122022 |
| As time | 21608 seconds = 6 h 0 min 8 s |
Is 21608 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21608 ÷ 2 = 10804) | 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 (21608 ÷ 4 = 5402) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | 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 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 | Yes (21608 ÷ 8 = 2701) | 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 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | 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 21608 a prime number?
No. 21608 = × 37 × 73, so it is divisible by 2.
What are the factors of 21608?
1, 2, 4, 8, 37, 73, 74, 146, 148, 292, 296, 584, 2701, 5402, 10804, 21608.
What is 21608 in binary?
101010001101000 (hexadecimal 5468, octal 52150).
What is the square root of 21608?
About 146.9966, exactly 2√5402.
Is 21608 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 21608?
It is a composite number with 16 divisors.