The number 55805
55805 is a composite number with 4 divisors. Its prime factorisation is 5 × 11161. Divisors (4): 1, 5, 11161, 55805.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 55805: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 5 × 11161, the product of two primes.
- 2
55805 is composite. Its prime factorisation is
- 3
The divisors add up to 66972; without 55805 itself that is 11167, so 55805 is deficient (11167 is less than 55805). Euler's totient φ(55805) = 44640 numbers up to 55805 share no factor with it.
- 4
The digits of 55805 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 91 steps to reach 1.
LaTeX source of the formulas on this page
\[ 55805 = 5 \times 11161 \]
55805 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 66972 |
| Euler totient φ(n) | 44640 |
| Square | 3114198025 |
| Cube | 173787820785125 |
| Square root | 236.230819 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 91 |
| Scientific notation | 5.5805 × |
55805 in other forms
| Form | Value |
|---|---|
| In words | fifty-five thousand eight hundred and five |
| Binary (base 2) | 1101100111111101 |
| Octal (base 8) | 154775 |
| Hexadecimal (base 16) | D9FD |
| Base 3 | 2211112212 |
| As time | 55805 seconds = 15 h 30 min 5 s |
Is 55805 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 | Yes (55805 ÷ 5 = 11161) | 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 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 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 55805 a prime number?
No. 55805 = 5 × 11161, so it is divisible by 5.
What are the factors of 55805?
1, 5, 11161, 55805.
What is 55805 in binary?
1101100111111101 (hexadecimal D9FD, octal 154775).
What is the square root of 55805?
About 236.2308.
Is 55805 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 55805?
55805 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 5 × 11161, the product of two primes.