The number 133
133 is a composite number with 4 divisors. Its prime factorisation is 7 × 19. Divisors (4): 1, 7, 19, 133.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 133: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 7; a semiprime: 7 × 19, the product of two primes.
- 2
133 is composite. Its prime factorisation is
- 3
The divisors add up to 160; without 133 itself that is 27, so 133 is deficient (27 is less than 133). Euler's totient φ(133) = 108 numbers up to 133 share no factor with it.
- 4
The digits of 133 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 28 steps to reach 1.
LaTeX source of the formulas on this page
\[ 133 = 7 \times 19 \]
133 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 160 |
| Euler totient φ(n) | 108 |
| Square | 17689 |
| Cube | 2352637 |
| Square root | 11.532563 |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 28 |
| Scientific notation | 1.33 × |
133 in other forms
| Form | Value |
|---|---|
| In words | one hundred and thirty-three |
| Roman numerals | CXXXIII |
| Binary (base 2) | 10000101 |
| Octal (base 8) | 205 |
| Hexadecimal (base 16) | 85 |
| Base 3 | 11221 |
| As time | 133 seconds = 2 min 13 s |
Is 133 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 | Yes (133 ÷ 7 = 19) | 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 7) | 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 1) | 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 133 a prime number?
No. 133 = 7 × 19, so it is divisible by 7.
What are the factors of 133?
1, 7, 19, 133.
What is 133 in binary?
10000101 (hexadecimal 85, octal 205).
What is the square root of 133?
About 11.5326.
What is 133 in Roman numerals?
CXXXIII.
Is 133 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 133?
133 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 7; a semiprime: 7 × 19, the product of two primes.