The number 81007
81007 is a composite number with 4 divisors. Its prime factorisation is 59 × 1373. Divisors (4): 1, 59, 1373, 81007.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81007: a semiprime: 59 × 1373, the product of two primes.
- 2
81007 is composite. Its prime factorisation is
- 3
The divisors add up to 82440; without 81007 itself that is 1433, so 81007 is deficient (1433 is less than 81007). Euler's totient φ(81007) = 79576 numbers up to 81007 share no factor with it.
- 4
The digits of 81007 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 275 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81007 = 59 \times 1373 \]
81007 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 82440 |
| Euler totient φ(n) | 79576 |
| Square | 6562134049 |
| Cube | 531578792907343 |
| Square root | 284.617287 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 275 |
| Scientific notation | 8.1007 × |
81007 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand and seven |
| Binary (base 2) | 10011110001101111 |
| Octal (base 8) | 236157 |
| Hexadecimal (base 16) | 13C6F |
| Base 3 | 11010010021 |
| As time | 81007 seconds = 22 h 30 min 7 s |
Is 81007 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 1) | 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 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 | No (remainder 7) | 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 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81007 a prime number?
No. 81007 = 59 × 1373, so it is divisible by 59.
What are the factors of 81007?
1, 59, 1373, 81007.
What is 81007 in binary?
10011110001101111 (hexadecimal 13C6F, octal 236157).
What is the square root of 81007?
About 284.6173.
Is 81007 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 81007?
81007 is a semiprime: 59 × 1373, the product of two primes.