The number 87439
87439 is a composite number with 4 divisors. Its prime factorisation is 11 × 7949. Divisors (4): 1, 11, 7949, 87439.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 87439: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 11 × 7949, the product of two primes.
- 2
87439 is composite. Its prime factorisation is
- 3
The divisors add up to 95400; without 87439 itself that is 7961, so 87439 is deficient (7961 is less than 87439). Euler's totient φ(87439) = 79480 numbers up to 87439 share no factor with it.
- 4
The digits of 87439 add up to 31, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 102 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87439 = 11 \times 7949 \]
87439 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 95400 |
| Euler totient φ(n) | 79480 |
| Square | 7645578721 |
| Cube | 668521757785519 |
| Square root | 295.700862 |
| Digit sum / digital root | 31 / 4 |
| Collatz steps to 1 | 102 |
| Scientific notation | 8.7439 × |
87439 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand four hundred and thirty-nine |
| Binary (base 2) | 10101010110001111 |
| Octal (base 8) | 252617 |
| Hexadecimal (base 16) | 1558F |
| Base 3 | 11102221111 |
| As time | 87439 seconds = 24 h 17 min 19 s |
Is 87439 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 4) | 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 | No (remainder 2) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (87439 ÷ 11 = 7949) | 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 87439 a prime number?
No. 87439 = 11 × 7949, so it is divisible by 11.
What are the factors of 87439?
1, 11, 7949, 87439.
What is 87439 in binary?
10101010110001111 (hexadecimal 1558F, octal 252617).
What is the square root of 87439?
About 295.7009.
Is 87439 divisible by 3?
No. Its digits add up to 31, which is not a multiple of 3.
What is special about the number 87439?
87439 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 11 × 7949, the product of two primes.