The number 77761
77761 is the 7644th prime number. Its only divisors are 1 and 77761.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 77761: the 7644th prime number.
- 2
77761 is prime, so its only factors are 1 and 77761. It is the 7644th prime; the next prime is 77773 and the one before is 77747.
- 3
The divisors add up to 77762; without 77761 itself that is 1, so 77761 is deficient (1 is less than 77761). Euler's totient φ(77761) = 77760 numbers up to 77761 share no factor with it.
- 4
The digits of 77761 add up to 28, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 125 steps to reach 1.
77761 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 77762 |
| Euler totient φ(n) | 77760 |
| Square | 6046773121 |
| Cube | 470203124662081 |
| Square root | 278.856594 |
| Digit sum / digital root | 28 / 1 |
| Collatz steps to 1 | 125 |
| Scientific notation | 7.7761 × |
77761 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand seven hundred and sixty-one |
| Binary (base 2) | 10010111111000001 |
| Octal (base 8) | 227701 |
| Hexadecimal (base 16) | 12FC1 |
| Base 3 | 10221200001 |
| As time | 77761 seconds = 21 h 36 min 1 s |
Is 77761 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 5) | 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 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 | No (remainder 2) | 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 77761 a prime number?
Yes. 77761 is divisible only by 1 and itself.
What are the factors of 77761?
1, 77761.
What is 77761 in binary?
10010111111000001 (hexadecimal 12FC1, octal 227701).
What is the square root of 77761?
About 278.8566.
Is 77761 divisible by 3?
No. Its digits add up to 28, which is not a multiple of 3.
What is special about the number 77761?
77761 is the 7644th prime number.