The number 81003
81003 is a triangular number: 1 + 2 + … + 402 = 81003. Its prime factorisation is 3 × 13 × 31 × 67. Divisors (16): 1, 3, 13, 31, 39, 67, 93, 201, 403, 871, 1209, 2077, 2613, 6231, 27001, 81003.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81003: a triangular number: 1 + 2 + … + 402 = 81003.
- 2
81003 is composite. Its prime factorisation is
- 3
The divisors add up to 121856; without 81003 itself that is 40853, so 81003 is deficient (40853 is less than 81003). Euler's totient φ(81003) = 47520 numbers up to 81003 share no factor with it.
- 4
The digits of 81003 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 244 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81003 = 3 \times 13 \times 31 \times 67 \]
81003 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 121856 |
| Euler totient φ(n) | 47520 |
| Square | 6561486009 |
| Cube | 531500051187027 |
| Square root | 284.610260 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 244 |
| Scientific notation | 8.1003 × |
81003 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand and three |
| Binary (base 2) | 10011110001101011 |
| Octal (base 8) | 236153 |
| Hexadecimal (base 16) | 13C6B |
| Base 3 | 11010010010 |
| As time | 81003 seconds = 22 h 30 min 3 s |
Is 81003 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 (81003 ÷ 3 = 27001) | 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 3) | 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 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | 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 81003 a prime number?
No. 81003 = 3 × 13 × 31 × 67, so it is divisible by 3.
What are the factors of 81003?
1, 3, 13, 31, 39, 67, 93, 201, 403, 871, 1209, 2077, 2613, 6231, 27001, 81003.
What is 81003 in binary?
10011110001101011 (hexadecimal 13C6B, octal 236153).
What is the square root of 81003?
About 284.6103.
Is 81003 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 81003?
81003 is a triangular number: 1 + 2 + … + 402 = 81003.