The number 42987
42987 is a composite number with 16 divisors. Its prime factorisation is 3 × 7 × 23 × 89. Divisors (16): 1, 3, 7, 21, 23, 69, 89, 161, 267, 483, 623, 1869, 2047, 6141, 14329, 42987.
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How to work it out
- 1
42987 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42987 is composite. Its prime factorisation is
- 3
The divisors add up to 69120; without 42987 itself that is 26133, so 42987 is deficient (26133 is less than 42987). Euler's totient φ(42987) = 23232 numbers up to 42987 share no factor with it.
- 4
The digits of 42987 add up to 30, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 194 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42987 = 3 \times 7 \times 23 \times 89 \]
42987 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 69120 |
| Euler totient φ(n) | 23232 |
| Square | 1847882169 |
| Cube | 79434910798803 |
| Square root | 207.333065 |
| Digit sum / digital root | 30 / 3 |
| Collatz steps to 1 | 194 |
| Scientific notation | 4.2987 × |
42987 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand nine hundred and eighty-seven |
| Binary (base 2) | 1010011111101011 |
| Octal (base 8) | 123753 |
| Hexadecimal (base 16) | A7EB |
| Base 3 | 2011222010 |
| As time | 42987 seconds = 11 h 56 min 27 s |
Is 42987 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 (42987 ÷ 3 = 14329) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | 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 | Yes (42987 ÷ 7 = 6141) | 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 3) | 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 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42987 a prime number?
No. 42987 = 3 × 7 × 23 × 89, so it is divisible by 3.
What are the factors of 42987?
1, 3, 7, 21, 23, 69, 89, 161, 267, 483, 623, 1869, 2047, 6141, 14329, 42987.
What is 42987 in binary?
1010011111101011 (hexadecimal A7EB, octal 123753).
What is the square root of 42987?
About 207.3331.
Is 42987 divisible by 3?
Yes. Its digits add up to 30, a multiple of 3.
What is special about the number 42987?
It is a composite number with 16 divisors.