The number 751
751 is the 133rd prime number. Its only divisors are 1 and 751.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 751: the 133rd prime number.
- 2
751 is prime, so its only factors are 1 and 751. It is the 133rd prime; the next prime is 757 and the one before is 743.
- 3
The divisors add up to 752; without 751 itself that is 1, so 751 is deficient (1 is less than 751). Euler's totient φ(751) = 750 numbers up to 751 share no factor with it.
- 4
The digits of 751 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 139 steps to reach 1.
751 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 752 |
| Euler totient φ(n) | 750 |
| Square | 564001 |
| Cube | 423564751 |
| Square root | 27.404379 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 139 |
| Scientific notation | 7.51 × |
751 in other forms
| Form | Value |
|---|---|
| In words | seven hundred and fifty-one |
| Roman numerals | DCCLI |
| Binary (base 2) | 1011101111 |
| Octal (base 8) | 1357 |
| Hexadecimal (base 16) | 2EF |
| Base 3 | 1000211 |
| As time | 751 seconds = 12 min 31 s |
Is 751 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 3) | 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 2) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 751 a prime number?
Yes. 751 is divisible only by 1 and itself.
What are the factors of 751?
1, 751.
What is 751 in binary?
1011101111 (hexadecimal 2EF, octal 1357).
What is the square root of 751?
About 27.4044.
What is 751 in Roman numerals?
DCCLI.
Is 751 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 751?
751 is the 133rd prime number.