The number 42420
42420 is a composite number with 48 divisors. Its prime factorisation is × 3 × 5 × 7 × 101. Divisors (48): 1, 2, 3, 4, 5, 6, 7, 10, 12, 14, 15, 20, 21, 28, 30, 35 … 42420.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42420: a Harshad number: divisible by its digit sum 12.
- 2
42420 is composite. Its prime factorisation is
- 3
The divisors add up to 137088; without 42420 itself that is 94668, so 42420 is abundant (94668 is more than 42420). Euler's totient φ(42420) = 9600 numbers up to 42420 share no factor with it.
- 4
The digits of 42420 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 150 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42420 = 2^{2} \times 3 \times 5 \times 7 \times 101 \]42420 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 48 |
| Sum of divisors | 137088 |
| Euler totient φ(n) | 9600 |
| Square | 1799456400 |
| Cube | 76332940488000 |
| Square root | 205.961161 (= 2√10605) |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 150 |
| Scientific notation | 4.242 × |
42420 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand four hundred and twenty |
| Binary (base 2) | 1010010110110100 |
| Octal (base 8) | 122664 |
| Hexadecimal (base 16) | A5B4 |
| Base 3 | 2011012010 |
| As time | 42420 seconds = 11 h 47 min 0 s |
Is 42420 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42420 ÷ 2 = 21210) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (42420 ÷ 3 = 14140) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (42420 ÷ 4 = 10605) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (42420 ÷ 5 = 8484) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (42420 ÷ 6 = 7070) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (42420 ÷ 7 = 6060) | 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 | Yes (42420 ÷ 10 = 4242) | 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 | Yes (42420 ÷ 12 = 3535) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42420 a prime number?
No. 42420 = × 3 × 5 × 7 × 101, so it is divisible by 2.
What are the factors of 42420?
1, 2, 3, 4, 5, 6, 7, 10, 12, 14, 15, 20, 21, 28, 30, 35, 42, 60, 70, 84, 101, 105, 140, 202, 210, 303, 404, 420, 505, 606, 707, 1010, 1212, 1414, 1515, 2020, 2121, 2828, 3030, 3535, 4242, 6060, 7070, 8484, 10605, 14140, 21210, 42420.
What is 42420 in binary?
1010010110110100 (hexadecimal A5B4, octal 122664).
What is the square root of 42420?
About 205.9612, exactly 2√10605.
Is 42420 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 42420?
42420 is a Harshad number: divisible by its digit sum 12.