The number 478
478 is a composite number with 4 divisors. Its prime factorisation is 2 × 239. Divisors (4): 1, 2, 239, 478.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 478: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 2 × 239, the product of two primes.
- 2
478 is composite. Its prime factorisation is
- 3
The divisors add up to 720; without 478 itself that is 242, so 478 is deficient (242 is less than 478). Euler's totient φ(478) = 238 numbers up to 478 share no factor with it.
- 4
The digits of 478 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 53 steps to reach 1.
LaTeX source of the formulas on this page
\[ 478 = 2 \times 239 \]
478 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 720 |
| Euler totient φ(n) | 238 |
| Square | 228484 |
| Cube | 109215352 |
| Square root | 21.863211 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 53 |
| Scientific notation | 4.78 × |
478 in other forms
| Form | Value |
|---|---|
| In words | four hundred and seventy-eight |
| Roman numerals | CDLXXVIII |
| Binary (base 2) | 111011110 |
| Octal (base 8) | 736 |
| Hexadecimal (base 16) | 1DE |
| Base 3 | 122201 |
| As time | 478 seconds = 7 min 58 s |
Is 478 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (478 ÷ 2 = 239) | 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 2) | 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 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 6) | 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 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 478 a prime number?
No. 478 = 2 × 239, so it is divisible by 2.
What are the factors of 478?
1, 2, 239, 478.
What is 478 in binary?
111011110 (hexadecimal 1DE, octal 736).
What is the square root of 478?
About 21.8632.
What is 478 in Roman numerals?
CDLXXVIII.
Is 478 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 478?
478 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 2 × 239, the product of two primes.