The number 7813
7813 is a composite number with 4 divisors. Its prime factorisation is 13 × 601. Divisors (4): 1, 13, 601, 7813.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 7813: a semiprime: 13 × 601, the product of two primes.
- 2
7813 is composite. Its prime factorisation is
- 3
The divisors add up to 8428; without 7813 itself that is 615, so 7813 is deficient (615 is less than 7813). Euler's totient φ(7813) = 7200 numbers up to 7813 share no factor with it.
- 4
The digits of 7813 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 39 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7813 = 13 \times 601 \]
7813 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 8428 |
| Euler totient φ(n) | 7200 |
| Square | 61042969 |
| Cube | 476928716797 |
| Square root | 88.391176 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 39 |
| Scientific notation | 7.813 × |
7813 in other forms
| Form | Value |
|---|---|
| In words | seven thousand eight hundred and thirteen |
| Binary (base 2) | 1111010000101 |
| Octal (base 8) | 17205 |
| Hexadecimal (base 16) | 1E85 |
| Base 3 | 101201101 |
| As time | 7813 seconds = 2 h 10 min 13 s |
Is 7813 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 3) | 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 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 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | 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 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 7813 a prime number?
No. 7813 = 13 × 601, so it is divisible by 13.
What are the factors of 7813?
1, 13, 601, 7813.
What is 7813 in binary?
1111010000101 (hexadecimal 1E85, octal 17205).
What is the square root of 7813?
About 88.3912.
Is 7813 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 7813?
7813 is a semiprime: 13 × 601, the product of two primes.