The number 81351
81351 is a composite number with 16 divisors. Its prime factorisation is × 23 × 131. Divisors (16): 1, 3, 9, 23, 27, 69, 131, 207, 393, 621, 1179, 3013, 3537, 9039, 27117, 81351.
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How to work it out
- 1
What is special about 81351: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
81351 is composite. Its prime factorisation is
- 3
The divisors add up to 126720; without 81351 itself that is 45369, so 81351 is deficient (45369 is less than 81351). Euler's totient φ(81351) = 51480 numbers up to 81351 share no factor with it.
- 4
The digits of 81351 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 63 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81351 = 3^{3} \times 23 \times 131 \]81351 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 126720 |
| Euler totient φ(n) | 51480 |
| Square | 6617985201 |
| Cube | 538379714086551 |
| Square root | 285.220967 (= 3√9039) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 63 |
| Scientific notation | 8.1351 × |
81351 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand three hundred and fifty-one |
| Binary (base 2) | 10011110111000111 |
| Octal (base 8) | 236707 |
| Hexadecimal (base 16) | 13DC7 |
| Base 3 | 11010121000 |
| As time | 81351 seconds = 22 h 35 min 51 s |
Is 81351 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 (81351 ÷ 3 = 27117) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | 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 4) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (81351 ÷ 9 = 9039) | 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 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81351 a prime number?
No. 81351 = × 23 × 131, so it is divisible by 3.
What are the factors of 81351?
1, 3, 9, 23, 27, 69, 131, 207, 393, 621, 1179, 3013, 3537, 9039, 27117, 81351.
What is 81351 in binary?
10011110111000111 (hexadecimal 13DC7, octal 236707).
What is the square root of 81351?
About 285.2210, exactly 3√9039.
Is 81351 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 81351?
81351 is a happy number: repeatedly adding the squares of its digits reaches 1.