The number 797
797 is a palindromic prime: it reads the same backwards and is prime, the 139th prime number and a palindrome: it reads 797 backwards too. Its only divisors are 1 and 797.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 797: a palindromic prime: it reads the same backwards and is prime; the 139th prime number; a palindrome: it reads 797 backwards too.
- 2
797 is prime, so its only factors are 1 and 797. It is the 139th prime; the next prime is 809 and the one before is 787.
- 3
The divisors add up to 798; without 797 itself that is 1, so 797 is deficient (1 is less than 797). Euler's totient φ(797) = 796 numbers up to 797 share no factor with it.
- 4
The digits of 797 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 121 steps to reach 1.
797 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 798 |
| Euler totient φ(n) | 796 |
| Square | 635209 |
| Cube | 506261573 |
| Square root | 28.231188 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 121 |
| Scientific notation | 7.97 × |
797 in other forms
| Form | Value |
|---|---|
| In words | seven hundred and ninety-seven |
| Roman numerals | DCCXCVII |
| Binary (base 2) | 1100011101 |
| Octal (base 8) | 1435 |
| Hexadecimal (base 16) | 31D |
| Base 3 | 1002112 |
| As time | 797 seconds = 13 min 17 s |
Is 797 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 2) | 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 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | 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 797 a prime number?
Yes. 797 is divisible only by 1 and itself.
What are the factors of 797?
1, 797.
What is 797 in binary?
1100011101 (hexadecimal 31D, octal 1435).
What is the square root of 797?
About 28.2312.
What is 797 in Roman numerals?
DCCXCVII.
Is 797 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 797?
797 is a palindromic prime: it reads the same backwards and is prime; the 139th prime number; a palindrome: it reads 797 backwards too.