The number 51987
51987 is a composite number with 16 divisors. Its prime factorisation is 3 × 13 × 31 × 43. Divisors (16): 1, 3, 13, 31, 39, 43, 93, 129, 403, 559, 1209, 1333, 1677, 3999, 17329, 51987.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
51987 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
51987 is composite. Its prime factorisation is
- 3
The divisors add up to 78848; without 51987 itself that is 26861, so 51987 is deficient (26861 is less than 51987). Euler's totient φ(51987) = 30240 numbers up to 51987 share no factor with it.
- 4
The digits of 51987 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 127 steps to reach 1.
LaTeX source of the formulas on this page
\[ 51987 = 3 \times 13 \times 31 \times 43 \]
51987 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 78848 |
| Euler totient φ(n) | 30240 |
| Square | 2702648169 |
| Cube | 140502570361803 |
| Square root | 228.006579 |
| Digit sum / digital root | 30 / 3 |
| Collatz steps to 1 | 127 |
| Scientific notation | 5.1987 × |
51987 in other forms
| Form | Value |
|---|---|
| In words | fifty-one thousand nine hundred and eighty-seven |
| Binary (base 2) | 1100101100010011 |
| Octal (base 8) | 145423 |
| Hexadecimal (base 16) | CB13 |
| Base 3 | 2122022110 |
| As time | 51987 seconds = 14 h 26 min 27 s |
Is 51987 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 (51987 ÷ 3 = 17329) | 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 | No (remainder 5) | 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 1) | 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 51987 a prime number?
No. 51987 = 3 × 13 × 31 × 43, so it is divisible by 3.
What are the factors of 51987?
1, 3, 13, 31, 39, 43, 93, 129, 403, 559, 1209, 1333, 1677, 3999, 17329, 51987.
What is 51987 in binary?
1100101100010011 (hexadecimal CB13, octal 145423).
What is the square root of 51987?
About 228.0066.
Is 51987 divisible by 3?
Yes. Its digits add up to 30, a multiple of 3.
What is special about the number 51987?
It is a composite number with 16 divisors.