The number 51813
51813 is a composite number with 16 divisors. Its prime factorisation is × 19 × 101. Divisors (16): 1, 3, 9, 19, 27, 57, 101, 171, 303, 513, 909, 1919, 2727, 5757, 17271, 51813.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 51813: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
51813 is composite. Its prime factorisation is
- 3
The divisors add up to 81600; without 51813 itself that is 29787, so 51813 is deficient (29787 is less than 51813). Euler's totient φ(51813) = 32400 numbers up to 51813 share no factor with it.
- 4
The digits of 51813 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 171 steps to reach 1.
LaTeX source of the formulas on this page
\[ 51813 = 3^{3} \times 19 \times 101 \]51813 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 81600 |
| Euler totient φ(n) | 32400 |
| Square | 2684586969 |
| Cube | 139096504624797 |
| Square root | 227.624691 (= 3√5757) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 171 |
| Scientific notation | 5.1813 × |
51813 in other forms
| Form | Value |
|---|---|
| In words | fifty-one thousand eight hundred and thirteen |
| Binary (base 2) | 1100101001100101 |
| Octal (base 8) | 145145 |
| Hexadecimal (base 16) | CA65 |
| Base 3 | 2122002000 |
| As time | 51813 seconds = 14 h 23 min 33 s |
Is 51813 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 | Yes (51813 ÷ 3 = 17271) | 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 3) | 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 | Yes (51813 ÷ 9 = 5757) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 51813 a prime number?
No. 51813 = × 19 × 101, so it is divisible by 3.
What are the factors of 51813?
1, 3, 9, 19, 27, 57, 101, 171, 303, 513, 909, 1919, 2727, 5757, 17271, 51813.
What is 51813 in binary?
1100101001100101 (hexadecimal CA65, octal 145145).
What is the square root of 51813?
About 227.6247, exactly 3√5757.
Is 51813 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 51813?
51813 is a happy number: repeatedly adding the squares of its digits reaches 1.