The number 5555
5555 is a palindrome: it reads 5555 backwards too. Its prime factorisation is 5 × 11 × 101. Divisors (8): 1, 5, 11, 55, 101, 505, 1111, 5555.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 5555: a palindrome: it reads 5555 backwards too; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
5555 is composite. Its prime factorisation is
- 3
The divisors add up to 7344; without 5555 itself that is 1789, so 5555 is deficient (1789 is less than 5555). Euler's totient φ(5555) = 4000 numbers up to 5555 share no factor with it.
- 4
The digits of 5555 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 129 steps to reach 1.
LaTeX source of the formulas on this page
\[ 5555 = 5 \times 11 \times 101 \]
5555 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 7344 |
| Euler totient φ(n) | 4000 |
| Square | 30858025 |
| Cube | 171416328875 |
| Square root | 74.531872 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 129 |
| Scientific notation | 5.555 × |
5555 in other forms
| Form | Value |
|---|---|
| In words | five thousand five hundred and fifty-five |
| Binary (base 2) | 1010110110011 |
| Octal (base 8) | 12663 |
| Hexadecimal (base 16) | 15B3 |
| Base 3 | 21121202 |
| As time | 5555 seconds = 1 h 32 min 35 s |
Is 5555 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (5555 ÷ 5 = 1111) | 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 4) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | 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 | Yes (5555 ÷ 11 = 505) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 5555 a prime number?
No. 5555 = 5 × 11 × 101, so it is divisible by 5.
What are the factors of 5555?
1, 5, 11, 55, 101, 505, 1111, 5555.
What is 5555 in binary?
1010110110011 (hexadecimal 15B3, octal 12663).
What is the square root of 5555?
About 74.5319.
Is 5555 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 5555?
5555 is a palindrome: it reads 5555 backwards too; a happy number: repeatedly adding the squares of its digits reaches 1.