The number 7381
7381 is a triangular number: 1 + 2 + ā¦ + 121 = 7381. Its prime factorisation is Ć 61. Divisors (6): 1, 11, 61, 121, 671, 7381.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 7381: a triangular number: 1 + 2 + ā¦ + 121 = 7381.
- 2
7381 is composite. Its prime factorisation is
- 3
The divisors add up to 8246; without 7381 itself that is 865, so 7381 is deficient (865 is less than 7381). Euler's totient Ļ(7381) = 6600 numbers up to 7381 share no factor with it.
- 4
The digits of 7381 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 39 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7381 = 11^{2} \times 61 \]7381 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 8246 |
| Euler totient Ļ(n) | 6600 |
| Square | 54479161 |
| Cube | 402110687341 |
| Square root | 85.912746 (= 11ā61) |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 39 |
| Scientific notation | 7.381 Ć |
7381 in other forms
| Form | Value |
|---|---|
| In words | seven thousand three hundred and eighty-one |
| Binary (base 2) | 1110011010101 |
| Octal (base 8) | 16325 |
| Hexadecimal (base 16) | 1CD5 |
| Base 3 | 101010101 |
| As time | 7381 seconds = 2 h 3 min 1 s |
Is 7381 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 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | 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 | Yes (7381 Ć· 11 = 671) | 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 7381 a prime number?
No. 7381 = Ć 61, so it is divisible by 11.
What are the factors of 7381?
1, 11, 61, 121, 671, 7381.
What is 7381 in binary?
1110011010101 (hexadecimal 1CD5, octal 16325).
What is the square root of 7381?
About 85.9127, exactly 11ā61.
Is 7381 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 7381?
7381 is a triangular number: 1 + 2 + ā¦ + 121 = 7381.