The number 71261
71261 is a twin prime (71261 and 71263 are both prime) and the 7055th prime number. Its only divisors are 1 and 71261.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 71261: a twin prime (71261 and 71263 are both prime); the 7055th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
71261 is prime, so its only factors are 1 and 71261. It is the 7055th prime; the next prime is 71263 and the one before is 71257.
- 3
The divisors add up to 71262; without 71261 itself that is 1, so 71261 is deficient (1 is less than 71261). Euler's totient φ(71261) = 71260 numbers up to 71261 share no factor with it.
- 4
The digits of 71261 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 99 steps to reach 1.
71261 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 71262 |
| Euler totient φ(n) | 71260 |
| Square | 5078130121 |
| Cube | 361872630552581 |
| Square root | 266.947560 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 99 |
| Scientific notation | 7.1261 × |
71261 in other forms
| Form | Value |
|---|---|
| In words | seventy-one thousand two hundred and sixty-one |
| Binary (base 2) | 10001011001011101 |
| Octal (base 8) | 213135 |
| Hexadecimal (base 16) | 1165D |
| Base 3 | 10121202022 |
| As time | 71261 seconds = 19 h 47 min 41 s |
Is 71261 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 1) | 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 1) | 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 8) | 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 3) | 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 71261 a prime number?
Yes. 71261 is divisible only by 1 and itself.
What are the factors of 71261?
1, 71261.
What is 71261 in binary?
10001011001011101 (hexadecimal 1165D, octal 213135).
What is the square root of 71261?
About 266.9476.
Is 71261 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 71261?
71261 is a twin prime (71261 and 71263 are both prime); the 7055th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.