The number 81437
81437 is a composite number with 8 divisors. Its prime factorisation is 31 × 37 × 71. Divisors (8): 1, 31, 37, 71, 1147, 2201, 2627, 81437.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81437: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
81437 is composite. Its prime factorisation is
- 3
The divisors add up to 87552; without 81437 itself that is 6115, so 81437 is deficient (6115 is less than 81437). Euler's totient φ(81437) = 75600 numbers up to 81437 share no factor with it.
- 4
The digits of 81437 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 37 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81437 = 31 \times 37 \times 71 \]
81437 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 87552 |
| Euler totient φ(n) | 75600 |
| Square | 6631984969 |
| Cube | 540088959920453 |
| Square root | 285.371687 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 37 |
| Scientific notation | 8.1437 × |
81437 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand four hundred and thirty-seven |
| Binary (base 2) | 10011111000011101 |
| Octal (base 8) | 237035 |
| Hexadecimal (base 16) | 13E1D |
| Base 3 | 11010201012 |
| As time | 81437 seconds = 22 h 37 min 17 s |
Is 81437 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 | No (remainder 2) | 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 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | 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 | No (remainder 5) | 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 7) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81437 a prime number?
No. 81437 = 31 × 37 × 71, so it is divisible by 31.
What are the factors of 81437?
1, 31, 37, 71, 1147, 2201, 2627, 81437.
What is 81437 in binary?
10011111000011101 (hexadecimal 13E1D, octal 237035).
What is the square root of 81437?
About 285.3717.
Is 81437 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 81437?
81437 is a happy number: repeatedly adding the squares of its digits reaches 1.