The number 21488
21488 is a composite number with 20 divisors. Its prime factorisation is × 17 × 79. Divisors (20): 1, 2, 4, 8, 16, 17, 34, 68, 79, 136, 158, 272, 316, 632, 1264, 1343 … 21488.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21488 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21488 is composite. Its prime factorisation is
- 3
The divisors add up to 44640; without 21488 itself that is 23152, so 21488 is abundant (23152 is more than 21488). Euler's totient φ(21488) = 9984 numbers up to 21488 share no factor with it.
- 4
The digits of 21488 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 100 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21488 = 2^{4} \times 17 \times 79 \]21488 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 44640 |
| Euler totient φ(n) | 9984 |
| Square | 461734144 |
| Cube | 9921743286272 |
| Square root | 146.587858 (= 4√1343) |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 100 |
| Scientific notation | 2.1488 × |
21488 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and eighty-eight |
| Binary (base 2) | 101001111110000 |
| Octal (base 8) | 51760 |
| Hexadecimal (base 16) | 53F0 |
| Base 3 | 1002110212 |
| As time | 21488 seconds = 5 h 58 min 8 s |
Is 21488 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21488 ÷ 2 = 10744) | 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 (21488 ÷ 4 = 5372) | 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 5) | 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 (21488 ÷ 8 = 2686) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | 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 5) | 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 21488 a prime number?
No. 21488 = × 17 × 79, so it is divisible by 2.
What are the factors of 21488?
1, 2, 4, 8, 16, 17, 34, 68, 79, 136, 158, 272, 316, 632, 1264, 1343, 2686, 5372, 10744, 21488.
What is 21488 in binary?
101001111110000 (hexadecimal 53F0, octal 51760).
What is the square root of 21488?
About 146.5879, exactly 4√1343.
Is 21488 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 21488?
It is a composite number with 20 divisors.