The number 19742
19742 is a composite number with 4 divisors. Its prime factorisation is 2 × 9871. Divisors (4): 1, 2, 9871, 19742.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 19742: a semiprime: 2 × 9871, the product of two primes.
- 2
19742 is composite. Its prime factorisation is
- 3
The divisors add up to 29616; without 19742 itself that is 9874, so 19742 is deficient (9874 is less than 19742). Euler's totient φ(19742) = 9870 numbers up to 19742 share no factor with it.
- 4
The digits of 19742 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 198 steps to reach 1.
LaTeX source of the formulas on this page
\[ 19742 = 2 \times 9871 \]
19742 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 29616 |
| Euler totient φ(n) | 9870 |
| Square | 389746564 |
| Cube | 7694376666488 |
| Square root | 140.506228 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 198 |
| Scientific notation | 1.9742 × |
19742 in other forms
| Form | Value |
|---|---|
| In words | nineteen thousand seven hundred and forty-two |
| Binary (base 2) | 100110100011110 |
| Octal (base 8) | 46436 |
| Hexadecimal (base 16) | 4D1E |
| Base 3 | 1000002012 |
| As time | 19742 seconds = 5 h 29 min 2 s |
Is 19742 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (19742 ÷ 2 = 9871) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | 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 2) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 19742 a prime number?
No. 19742 = 2 × 9871, so it is divisible by 2.
What are the factors of 19742?
1, 2, 9871, 19742.
What is 19742 in binary?
100110100011110 (hexadecimal 4D1E, octal 46436).
What is the square root of 19742?
About 140.5062.
Is 19742 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 19742?
19742 is a semiprime: 2 × 9871, the product of two primes.