The number 213
213 is a composite number with 4 divisors. Its prime factorisation is 3 × 71. Divisors (4): 1, 3, 71, 213.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 213: a semiprime: 3 × 71, the product of two primes.
- 2
213 is composite. Its prime factorisation is
- 3
The divisors add up to 288; without 213 itself that is 75, so 213 is deficient (75 is less than 213). Euler's totient φ(213) = 140 numbers up to 213 share no factor with it.
- 4
The digits of 213 add up to 6, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 13 steps to reach 1.
LaTeX source of the formulas on this page
\[ 213 = 3 \times 71 \]
213 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 288 |
| Euler totient φ(n) | 140 |
| Square | 45369 |
| Cube | 9663597 |
| Square root | 14.594520 |
| Digit sum / digital root | 6 / 6 |
| Collatz steps to 1 | 13 |
| Scientific notation | 2.13 × |
213 in other forms
| Form | Value |
|---|---|
| In words | two hundred and thirteen |
| Roman numerals | CCXIII |
| Binary (base 2) | 11010101 |
| Octal (base 8) | 325 |
| Hexadecimal (base 16) | D5 |
| Base 3 | 21220 |
| As time | 213 seconds = 3 min 33 s |
Is 213 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 | Yes (213 ÷ 3 = 71) | 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 3) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | 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 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 213 a prime number?
No. 213 = 3 × 71, so it is divisible by 3.
What are the factors of 213?
1, 3, 71, 213.
What is 213 in binary?
11010101 (hexadecimal D5, octal 325).
What is the square root of 213?
About 14.5945.
What is 213 in Roman numerals?
CCXIII.
Is 213 divisible by 3?
Yes. Its digits add up to 6, a multiple of 3.
What is special about the number 213?
213 is a semiprime: 3 × 71, the product of two primes.