The number 72021
72021 is a composite number with 4 divisors. Its prime factorisation is 3 × 24007. Divisors (4): 1, 3, 24007, 72021.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 72021: a semiprime: 3 × 24007, the product of two primes.
- 2
72021 is composite. Its prime factorisation is
- 3
The divisors add up to 96032; without 72021 itself that is 24011, so 72021 is deficient (24011 is less than 72021). Euler's totient φ(72021) = 48012 numbers up to 72021 share no factor with it.
- 4
The digits of 72021 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 50 steps to reach 1.
LaTeX source of the formulas on this page
\[ 72021 = 3 \times 24007 \]
72021 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 96032 |
| Euler totient φ(n) | 48012 |
| Square | 5187024441 |
| Cube | 373574687265261 |
| Square root | 268.367286 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 50 |
| Scientific notation | 7.2021 × |
72021 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand and twenty-one |
| Binary (base 2) | 10001100101010101 |
| Octal (base 8) | 214525 |
| Hexadecimal (base 16) | 11955 |
| Base 3 | 10122210110 |
| As time | 72021 seconds = 20 h 0 min 21 s |
Is 72021 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 (72021 ÷ 3 = 24007) | 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 1) | 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 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 | No (remainder 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | 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 72021 a prime number?
No. 72021 = 3 × 24007, so it is divisible by 3.
What are the factors of 72021?
1, 3, 24007, 72021.
What is 72021 in binary?
10001100101010101 (hexadecimal 11955, octal 214525).
What is the square root of 72021?
About 268.3673.
Is 72021 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 72021?
72021 is a semiprime: 3 × 24007, the product of two primes.