The number 87787
87787 is a composite number with 4 divisors. Its prime factorisation is 7 × 12541. Divisors (4): 1, 7, 12541, 87787.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 87787: a semiprime: 7 × 12541, the product of two primes.
- 2
87787 is composite. Its prime factorisation is
- 3
The divisors add up to 100336; without 87787 itself that is 12549, so 87787 is deficient (12549 is less than 87787). Euler's totient φ(87787) = 75240 numbers up to 87787 share no factor with it.
- 4
The digits of 87787 add up to 37, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 120 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87787 = 7 \times 12541 \]
87787 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 100336 |
| Euler totient φ(n) | 75240 |
| Square | 7706557369 |
| Cube | 676535551752403 |
| Square root | 296.288711 |
| Digit sum / digital root | 37 / 1 |
| Collatz steps to 1 | 120 |
| Scientific notation | 8.7787 × |
87787 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand seven hundred and eighty-seven |
| Binary (base 2) | 10101011011101011 |
| Octal (base 8) | 253353 |
| Hexadecimal (base 16) | 156EB |
| Base 3 | 11110102101 |
| As time | 87787 seconds = 24 h 23 min 7 s |
Is 87787 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 | No (remainder 1) | 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (87787 ÷ 7 = 12541) | 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 1) | 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 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 87787 a prime number?
No. 87787 = 7 × 12541, so it is divisible by 7.
What are the factors of 87787?
1, 7, 12541, 87787.
What is 87787 in binary?
10101011011101011 (hexadecimal 156EB, octal 253353).
What is the square root of 87787?
About 296.2887.
Is 87787 divisible by 3?
No. Its digits add up to 37, which is not a multiple of 3.
What is special about the number 87787?
87787 is a semiprime: 7 × 12541, the product of two primes.