The number 1720
1720 is a composite number with 16 divisors. Its prime factorisation is × 5 × 43. Divisors (16): 1, 2, 4, 5, 8, 10, 20, 40, 43, 86, 172, 215, 344, 430, 860, 1720.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1720: a Harshad number: divisible by its digit sum 10.
- 2
1720 is composite. Its prime factorisation is
- 3
The divisors add up to 3960; without 1720 itself that is 2240, so 1720 is abundant (2240 is more than 1720). Euler's totient φ(1720) = 672 numbers up to 1720 share no factor with it.
- 4
The digits of 1720 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 104 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1720 = 2^{3} \times 5 \times 43 \]1720 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 3960 |
| Euler totient φ(n) | 672 |
| Square | 2958400 |
| Cube | 5088448000 |
| Square root | 41.472883 (= 2√430) |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 104 |
| Scientific notation | 1.72 × |
1720 in other forms
| Form | Value |
|---|---|
| In words | one thousand seven hundred and twenty |
| Roman numerals | MDCCXX |
| Binary (base 2) | 11010111000 |
| Octal (base 8) | 3270 |
| Hexadecimal (base 16) | 6B8 |
| Base 3 | 2100201 |
| As time | 1720 seconds = 28 min 40 s |
Is 1720 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1720 ÷ 2 = 860) | 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 (1720 ÷ 4 = 430) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (1720 ÷ 5 = 344) | 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 5) | 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 (1720 ÷ 8 = 215) | 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 (1720 ÷ 10 = 172) | 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 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1720 a prime number?
No. 1720 = × 5 × 43, so it is divisible by 2.
What are the factors of 1720?
1, 2, 4, 5, 8, 10, 20, 40, 43, 86, 172, 215, 344, 430, 860, 1720.
What is 1720 in binary?
11010111000 (hexadecimal 6B8, octal 3270).
What is the square root of 1720?
About 41.4729, exactly 2√430.
What is 1720 in Roman numerals?
MDCCXX.
Is 1720 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 1720?
1720 is a Harshad number: divisible by its digit sum 10.