The number 81241
81241 is a composite number with 4 divisors. Its prime factorisation is 137 × 593. Divisors (4): 1, 137, 593, 81241.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81241: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 137 × 593, the product of two primes.
- 2
81241 is composite. Its prime factorisation is
- 3
The divisors add up to 81972; without 81241 itself that is 731, so 81241 is deficient (731 is less than 81241). Euler's totient φ(81241) = 80512 numbers up to 81241 share no factor with it.
- 4
The digits of 81241 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 37 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81241 = 137 \times 593 \]
81241 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 81972 |
| Euler totient φ(n) | 80512 |
| Square | 6600100081 |
| Cube | 536198730680521 |
| Square root | 285.028069 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 37 |
| Scientific notation | 8.1241 × |
81241 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand two hundred and forty-one |
| Binary (base 2) | 10011110101011001 |
| Octal (base 8) | 236531 |
| Hexadecimal (base 16) | 13D59 |
| Base 3 | 11010102221 |
| As time | 81241 seconds = 22 h 34 min 1 s |
Is 81241 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 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 1) | 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 1) | 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 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 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81241 a prime number?
No. 81241 = 137 × 593, so it is divisible by 137.
What are the factors of 81241?
1, 137, 593, 81241.
What is 81241 in binary?
10011110101011001 (hexadecimal 13D59, octal 236531).
What is the square root of 81241?
About 285.0281.
Is 81241 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 81241?
81241 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 137 × 593, the product of two primes.