The number 61989
61989 is a composite number with 4 divisors. Its prime factorisation is 3 × 20663. Divisors (4): 1, 3, 20663, 61989.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 61989: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 20663, the product of two primes.
- 2
61989 is composite. Its prime factorisation is
- 3
The divisors add up to 82656; without 61989 itself that is 20667, so 61989 is deficient (20667 is less than 61989). Euler's totient φ(61989) = 41324 numbers up to 61989 share no factor with it.
- 4
The digits of 61989 add up to 33, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 166 steps to reach 1.
LaTeX source of the formulas on this page
\[ 61989 = 3 \times 20663 \]
61989 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 82656 |
| Euler totient φ(n) | 41324 |
| Square | 3842636121 |
| Cube | 238201170504669 |
| Square root | 248.975902 |
| Digit sum / digital root | 33 / 6 |
| Collatz steps to 1 | 166 |
| Scientific notation | 6.1989 × |
61989 in other forms
| Form | Value |
|---|---|
| In words | sixty-one thousand nine hundred and eighty-nine |
| Binary (base 2) | 1111001000100101 |
| Octal (base 8) | 171045 |
| Hexadecimal (base 16) | F225 |
| Base 3 | 10011000220 |
| As time | 61989 seconds = 17 h 13 min 9 s |
Is 61989 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 (61989 ÷ 3 = 20663) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | 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 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 61989 a prime number?
No. 61989 = 3 × 20663, so it is divisible by 3.
What are the factors of 61989?
1, 3, 20663, 61989.
What is 61989 in binary?
1111001000100101 (hexadecimal F225, octal 171045).
What is the square root of 61989?
About 248.9759.
Is 61989 divisible by 3?
Yes. Its digits add up to 33, a multiple of 3.
What is special about the number 61989?
61989 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 20663, the product of two primes.