The number 26721
26721 is a composite number with 6 divisors. Its prime factorisation is × 2969. Divisors (6): 1, 3, 9, 2969, 8907, 26721.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 26721: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
26721 is composite. Its prime factorisation is
- 3
The divisors add up to 38610; without 26721 itself that is 11889, so 26721 is deficient (11889 is less than 26721). Euler's totient φ(26721) = 17808 numbers up to 26721 share no factor with it.
- 4
The digits of 26721 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 214 steps to reach 1.
LaTeX source of the formulas on this page
\[ 26721 = 3^{2} \times 2969 \]26721 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 38610 |
| Euler totient φ(n) | 17808 |
| Square | 714011841 |
| Cube | 19079110403361 |
| Square root | 163.465593 (= 3√2969) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 214 |
| Scientific notation | 2.6721 × |
26721 in other forms
| Form | Value |
|---|---|
| In words | twenty-six thousand seven hundred and twenty-one |
| Binary (base 2) | 110100001100001 |
| Octal (base 8) | 64141 |
| Hexadecimal (base 16) | 6861 |
| Base 3 | 1100122200 |
| As time | 26721 seconds = 7 h 25 min 21 s |
Is 26721 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 (26721 ÷ 3 = 8907) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (26721 ÷ 9 = 2969) | 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 2) | 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 26721 a prime number?
No. 26721 = × 2969, so it is divisible by 3.
What are the factors of 26721?
1, 3, 9, 2969, 8907, 26721.
What is 26721 in binary?
110100001100001 (hexadecimal 6861, octal 64141).
What is the square root of 26721?
About 163.4656, exactly 3√2969.
Is 26721 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 26721?
26721 is a happy number: repeatedly adding the squares of its digits reaches 1.