The number 355
355 is a composite number with 4 divisors. Its prime factorisation is 5 × 71. Divisors (4): 1, 5, 71, 355.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 355: a semiprime: 5 × 71, the product of two primes.
- 2
355 is composite. Its prime factorisation is
- 3
The divisors add up to 432; without 355 itself that is 77, so 355 is deficient (77 is less than 355). Euler's totient φ(355) = 280 numbers up to 355 share no factor with it.
- 4
The digits of 355 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 32 steps to reach 1.
LaTeX source of the formulas on this page
\[ 355 = 5 \times 71 \]
355 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 432 |
| Euler totient φ(n) | 280 |
| Square | 126025 |
| Cube | 44738875 |
| Square root | 18.841444 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 32 |
| Scientific notation | 3.55 × |
355 in other forms
| Form | Value |
|---|---|
| In words | three hundred and fifty-five |
| Roman numerals | CCCLV |
| Binary (base 2) | 101100011 |
| Octal (base 8) | 543 |
| Hexadecimal (base 16) | 163 |
| Base 3 | 111011 |
| As time | 355 seconds = 5 min 55 s |
Is 355 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 (355 ÷ 5 = 71) | 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 5) | 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 4) | 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 355 a prime number?
No. 355 = 5 × 71, so it is divisible by 5.
What are the factors of 355?
1, 5, 71, 355.
What is 355 in binary?
101100011 (hexadecimal 163, octal 543).
What is the square root of 355?
About 18.8414.
What is 355 in Roman numerals?
CCCLV.
Is 355 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 355?
355 is a semiprime: 5 × 71, the product of two primes.