The number 361
361 is a perfect square (19²). Its prime factorisation is . Divisors (3): 1, 19, 361.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 361: a perfect square (19²); the square of a prime (19²).
- 2
361 is composite. Its prime factorisation is
- 3
The divisors add up to 381; without 361 itself that is 20, so 361 is deficient (20 is less than 361). Euler's totient φ(361) = 342 numbers up to 361 share no factor with it.
- 4
The digits of 361 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 45 steps to reach 1.
LaTeX source of the formulas on this page
\[ 361 = 19^{2} \]361 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 3 |
| Sum of divisors | 381 |
| Euler totient φ(n) | 342 |
| Square | 130321 |
| Cube | 47045881 |
| Square root | 19 |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 45 |
| Scientific notation | 3.61 × |
| Perfect power |
361 in other forms
| Form | Value |
|---|---|
| In words | three hundred and sixty-one |
| Roman numerals | CCCLXI |
| Binary (base 2) | 101101001 |
| Octal (base 8) | 551 |
| Hexadecimal (base 16) | 169 |
| Base 3 | 111101 |
| As time | 361 seconds = 6 min 1 s |
Is 361 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 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | 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 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 1) | 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 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 361 a prime number?
No. 361 = , so it is divisible by 19.
What are the factors of 361?
1, 19, 361.
What is 361 in binary?
101101001 (hexadecimal 169, octal 551).
What is the square root of 361?
19, because 19 × 19 = 361.
What is 361 in Roman numerals?
CCCLXI.
Is 361 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 361?
361 is a perfect square (19²); the square of a prime (19²).