The number 3655
3655 is a triangular number: 1 + 2 + … + 85 = 3655. Its prime factorisation is 5 × 17 × 43. Divisors (8): 1, 5, 17, 43, 85, 215, 731, 3655.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 3655: a triangular number: 1 + 2 + … + 85 = 3655.
- 2
3655 is composite. Its prime factorisation is
- 3
The divisors add up to 4752; without 3655 itself that is 1097, so 3655 is deficient (1097 is less than 3655). Euler's totient φ(3655) = 2688 numbers up to 3655 share no factor with it.
- 4
The digits of 3655 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 118 steps to reach 1.
LaTeX source of the formulas on this page
\[ 3655 = 5 \times 17 \times 43 \]
3655 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 4752 |
| Euler totient φ(n) | 2688 |
| Square | 13359025 |
| Cube | 48827236375 |
| Square root | 60.456596 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 118 |
| Scientific notation | 3.655 × |
3655 in other forms
| Form | Value |
|---|---|
| In words | three thousand six hundred and fifty-five |
| Roman numerals | MMMDCLV |
| Binary (base 2) | 111001000111 |
| Octal (base 8) | 7107 |
| Hexadecimal (base 16) | E47 |
| Base 3 | 12000101 |
| As time | 3655 seconds = 1 h 0 min 55 s |
Is 3655 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (3655 ÷ 5 = 731) | 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 7) | 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 5) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 3655 a prime number?
No. 3655 = 5 × 17 × 43, so it is divisible by 5.
What are the factors of 3655?
1, 5, 17, 43, 85, 215, 731, 3655.
What is 3655 in binary?
111001000111 (hexadecimal E47, octal 7107).
What is the square root of 3655?
About 60.4566.
What is 3655 in Roman numerals?
MMMDCLV.
Is 3655 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 3655?
3655 is a triangular number: 1 + 2 + … + 85 = 3655.