The number 913
913 is a composite number with 4 divisors. Its prime factorisation is 11 × 83. Divisors (4): 1, 11, 83, 913.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 913: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 11 × 83, the product of two primes.
- 2
913 is composite. Its prime factorisation is
- 3
The divisors add up to 1008; without 913 itself that is 95, so 913 is deficient (95 is less than 913). Euler's totient φ(913) = 820 numbers up to 913 share no factor with it.
- 4
The digits of 913 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 129 steps to reach 1.
LaTeX source of the formulas on this page
\[ 913 = 11 \times 83 \]
913 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1008 |
| Euler totient φ(n) | 820 |
| Square | 833569 |
| Cube | 761048497 |
| Square root | 30.215890 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 129 |
| Scientific notation | 9.13 × |
913 in other forms
| Form | Value |
|---|---|
| In words | nine hundred and thirteen |
| Roman numerals | CMXIII |
| Binary (base 2) | 1110010001 |
| Octal (base 8) | 1621 |
| Hexadecimal (base 16) | 391 |
| Base 3 | 1020211 |
| As time | 913 seconds = 15 min 13 s |
Is 913 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 3) | 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 3) | 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 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (913 ÷ 11 = 83) | 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 913 a prime number?
No. 913 = 11 × 83, so it is divisible by 11.
What are the factors of 913?
1, 11, 83, 913.
What is 913 in binary?
1110010001 (hexadecimal 391, octal 1621).
What is the square root of 913?
About 30.2159.
What is 913 in Roman numerals?
CMXIII.
Is 913 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 913?
913 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 11 × 83, the product of two primes.