The number 19720
19720 is a composite number with 32 divisors. Its prime factorisation is × 5 × 17 × 29. Divisors (32): 1, 2, 4, 5, 8, 10, 17, 20, 29, 34, 40, 58, 68, 85, 116, 136 … 19720.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
19720 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
19720 is composite. Its prime factorisation is
- 3
The divisors add up to 48600; without 19720 itself that is 28880, so 19720 is abundant (28880 is more than 19720). Euler's totient φ(19720) = 7168 numbers up to 19720 share no factor with it.
- 4
The digits of 19720 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 74 steps to reach 1.
LaTeX source of the formulas on this page
\[ 19720 = 2^{3} \times 5 \times 17 \times 29 \]19720 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 48600 |
| Euler totient φ(n) | 7168 |
| Square | 388878400 |
| Cube | 7668682048000 |
| Square root | 140.427917 (= 2√4930) |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 74 |
| Scientific notation | 1.972 × |
19720 in other forms
| Form | Value |
|---|---|
| In words | nineteen thousand seven hundred and twenty |
| Binary (base 2) | 100110100001000 |
| Octal (base 8) | 46410 |
| Hexadecimal (base 16) | 4D08 |
| Base 3 | 1000001101 |
| As time | 19720 seconds = 5 h 28 min 40 s |
Is 19720 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (19720 ÷ 2 = 9860) | 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 | Yes (19720 ÷ 4 = 4930) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (19720 ÷ 5 = 3944) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 | Yes (19720 ÷ 8 = 2465) | 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 | Yes (19720 ÷ 10 = 1972) | 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 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 19720 a prime number?
No. 19720 = × 5 × 17 × 29, so it is divisible by 2.
What are the factors of 19720?
1, 2, 4, 5, 8, 10, 17, 20, 29, 34, 40, 58, 68, 85, 116, 136, 145, 170, 232, 290, 340, 493, 580, 680, 986, 1160, 1972, 2465, 3944, 4930, 9860, 19720.
What is 19720 in binary?
100110100001000 (hexadecimal 4D08, octal 46410).
What is the square root of 19720?
About 140.4279, exactly 2√4930.
Is 19720 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 19720?
It is a composite number with 32 divisors.