The number 172
172 is a composite number with 6 divisors. Its prime factorisation is × 43. Divisors (6): 1, 2, 4, 43, 86, 172.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
172 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
172 is composite. Its prime factorisation is
- 3
The divisors add up to 308; without 172 itself that is 136, so 172 is deficient (136 is less than 172). Euler's totient φ(172) = 84 numbers up to 172 share no factor with it.
- 4
The digits of 172 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 31 steps to reach 1.
LaTeX source of the formulas on this page
\[ 172 = 2^{2} \times 43 \]172 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 308 |
| Euler totient φ(n) | 84 |
| Square | 29584 |
| Cube | 5088448 |
| Square root | 13.114877 (= 2√43) |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 31 |
| Scientific notation | 1.72 × |
172 in other forms
| Form | Value |
|---|---|
| In words | one hundred and seventy-two |
| Roman numerals | CLXXII |
| Binary (base 2) | 10101100 |
| Octal (base 8) | 254 |
| Hexadecimal (base 16) | AC |
| Base 3 | 20101 |
| As time | 172 seconds = 2 min 52 s |
Is 172 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (172 ÷ 2 = 86) | 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 (172 ÷ 4 = 43) | 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 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 4) | 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 | No (remainder 2) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | 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 172 a prime number?
No. 172 = × 43, so it is divisible by 2.
What are the factors of 172?
1, 2, 4, 43, 86, 172.
What is 172 in binary?
10101100 (hexadecimal AC, octal 254).
What is the square root of 172?
About 13.1149, exactly 2√43.
What is 172 in Roman numerals?
CLXXII.
Is 172 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 172?
It is a composite number with 6 divisors.