The number 7801
7801 is a composite number with 4 divisors. Its prime factorisation is 29 × 269. Divisors (4): 1, 29, 269, 7801.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 7801: a semiprime: 29 × 269, the product of two primes.
- 2
7801 is composite. Its prime factorisation is
- 3
The divisors add up to 8100; without 7801 itself that is 299, so 7801 is deficient (299 is less than 7801). Euler's totient φ(7801) = 7504 numbers up to 7801 share no factor with it.
- 4
The digits of 7801 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 145 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7801 = 29 \times 269 \]
7801 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 8100 |
| Euler totient φ(n) | 7504 |
| Square | 60855601 |
| Cube | 474734543401 |
| Square root | 88.323270 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 145 |
| Scientific notation | 7.801 × |
7801 in other forms
| Form | Value |
|---|---|
| In words | seven thousand eight hundred and one |
| Binary (base 2) | 1111001111001 |
| Octal (base 8) | 17171 |
| Hexadecimal (base 16) | 1E79 |
| Base 3 | 101200221 |
| As time | 7801 seconds = 2 h 10 min 1 s |
Is 7801 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | 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 7801 a prime number?
No. 7801 = 29 × 269, so it is divisible by 29.
What are the factors of 7801?
1, 29, 269, 7801.
What is 7801 in binary?
1111001111001 (hexadecimal 1E79, octal 17171).
What is the square root of 7801?
About 88.3233.
Is 7801 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 7801?
7801 is a semiprime: 29 × 269, the product of two primes.