The number 71920
71920 is a composite number with 40 divisors. Its prime factorisation is × 5 × 29 × 31. Divisors (40): 1, 2, 4, 5, 8, 10, 16, 20, 29, 31, 40, 58, 62, 80, 116, 124 … 71920.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
71920 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
71920 is composite. Its prime factorisation is
- 3
The divisors add up to 178560; without 71920 itself that is 106640, so 71920 is abundant (106640 is more than 71920). Euler's totient φ(71920) = 26880 numbers up to 71920 share no factor with it.
- 4
The digits of 71920 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 81 steps to reach 1.
LaTeX source of the formulas on this page
\[ 71920 = 2^{4} \times 5 \times 29 \times 31 \]71920 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 40 |
| Sum of divisors | 178560 |
| Euler totient φ(n) | 26880 |
| Square | 5172486400 |
| Cube | 372005221888000 |
| Square root | 268.179045 (= 4√4495) |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 81 |
| Scientific notation | 7.192 × |
71920 in other forms
| Form | Value |
|---|---|
| In words | seventy-one thousand nine hundred and twenty |
| Binary (base 2) | 10001100011110000 |
| Octal (base 8) | 214360 |
| Hexadecimal (base 16) | 118F0 |
| Base 3 | 10122122201 |
| As time | 71920 seconds = 19 h 58 min 40 s |
Is 71920 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (71920 ÷ 2 = 35960) | 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 (71920 ÷ 4 = 17980) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (71920 ÷ 5 = 14384) | 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 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 | Yes (71920 ÷ 8 = 8990) | 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 (71920 ÷ 10 = 7192) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | 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 71920 a prime number?
No. 71920 = × 5 × 29 × 31, so it is divisible by 2.
What are the factors of 71920?
1, 2, 4, 5, 8, 10, 16, 20, 29, 31, 40, 58, 62, 80, 116, 124, 145, 155, 232, 248, 290, 310, 464, 496, 580, 620, 899, 1160, 1240, 1798, 2320, 2480, 3596, 4495, 7192, 8990, 14384, 17980, 35960, 71920.
What is 71920 in binary?
10001100011110000 (hexadecimal 118F0, octal 214360).
What is the square root of 71920?
About 268.1790, exactly 4√4495.
Is 71920 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 71920?
It is a composite number with 40 divisors.