The number 7428
7428 is a composite number with 12 divisors. Its prime factorisation is × 3 × 619. Divisors (12): 1, 2, 3, 4, 6, 12, 619, 1238, 1857, 2476, 3714, 7428.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 7428: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
7428 is composite. Its prime factorisation is
- 3
The divisors add up to 17360; without 7428 itself that is 9932, so 7428 is abundant (9932 is more than 7428). Euler's totient φ(7428) = 2472 numbers up to 7428 share no factor with it.
- 4
The digits of 7428 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 39 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7428 = 2^{2} \times 3 \times 619 \]7428 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 17360 |
| Euler totient φ(n) | 2472 |
| Square | 55175184 |
| Cube | 409841266752 |
| Square root | 86.185846 (= 2√1857) |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 39 |
| Scientific notation | 7.428 × |
7428 in other forms
| Form | Value |
|---|---|
| In words | seven thousand four hundred and twenty-eight |
| Binary (base 2) | 1110100000100 |
| Octal (base 8) | 16404 |
| Hexadecimal (base 16) | 1D04 |
| Base 3 | 101012010 |
| As time | 7428 seconds = 2 h 3 min 48 s |
Is 7428 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (7428 ÷ 2 = 3714) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (7428 ÷ 3 = 2476) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (7428 ÷ 4 = 1857) | 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 | Yes (7428 ÷ 6 = 1238) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | 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 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (7428 ÷ 12 = 619) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 7428 a prime number?
No. 7428 = × 3 × 619, so it is divisible by 2.
What are the factors of 7428?
1, 2, 3, 4, 6, 12, 619, 1238, 1857, 2476, 3714, 7428.
What is 7428 in binary?
1110100000100 (hexadecimal 1D04, octal 16404).
What is the square root of 7428?
About 86.1858, exactly 2√1857.
Is 7428 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 7428?
7428 is a happy number: repeatedly adding the squares of its digits reaches 1.