The number 28980

Q: Is 28980 a prime number?

No. 28980 = 2^2 × 3^2 × 5 × 7 × 23, so it is divisible by 2.

28980 is a composite number with 72 divisors. Its prime factorisation is $2^{2}$ × $3^{2}$ × 5 × 7 × 23. Divisors (72): 1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 14, 15, 18, 20, 21, 23 … 28980.

Number

Pick any whole number from 1 to 100,000.

28980 = 2^{2} \times 3^{2} \times 5 \times 7 \times 23

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How to work it out

1
28980 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
2
28980 is composite. Its prime factorisation is
$28980 = 2^{2} \times 3^{2} \times 5 \times 7 \times 23$
3
The divisors add up to 104832; without 28980 itself that is 75852, so 28980 is abundant (75852 is more than 28980). Euler's totient φ(28980) = 6336 numbers up to 28980 share no factor with it.
4
The digits of 28980 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 72 steps to reach 1.

LaTeX source of the formulas on this page

\[ 28980 = 2^{2} \times 3^{2} \times 5 \times 7 \times 23 \]

28980 at a glance

Property	Value
Type	composite
Number of divisors	72
Sum of divisors	104832
Euler totient φ(n)	6336
Square	839840400
Cube	24338574792000
Square root	170.235132 (= 6√805)
Digit sum / digital root	27 / 9
Collatz steps to 1	72
Scientific notation	2.898 × $10^{4}$

28980 in other forms

Form	Value
In words	twenty-eight thousand nine hundred and eighty
Binary (base 2)	111000100110100
Octal (base 8)	70464
Hexadecimal (base 16)	7134
Base 3	1110202100
As time	28980 seconds = 8 h 3 min 0 s

Is 28980 divisible by 2 to 12?

Divisor	Answer	Rule
2	Yes (28980 ÷ 2 = 14490)	A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8).
3	Yes (28980 ÷ 3 = 9660)	A number is divisible by 3 if the digits add up to a multiple of 3.
4	Yes (28980 ÷ 4 = 7245)	A number is divisible by 4 if the last two digits make a multiple of 4.
5	Yes (28980 ÷ 5 = 5796)	A number is divisible by 5 if the last digit is 0 or 5.
6	Yes (28980 ÷ 6 = 4830)	A number is divisible by 6 if it is divisible by both 2 and 3.
7	Yes (28980 ÷ 7 = 4140)	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	Yes (28980 ÷ 9 = 3220)	A number is divisible by 9 if the digits add up to a multiple of 9.
10	Yes (28980 ÷ 10 = 2898)	A number is divisible by 10 if the last digit is 0.
11	No (remainder 6)	A number is divisible by 11 if the alternating sum of the digits is a multiple of 11.
12	Yes (28980 ÷ 12 = 2415)	A number is divisible by 12 if it is divisible by both 3 and 4.

Questions

Is 28980 a prime number?

No. 28980 = $2^{2}$ × $3^{2}$ × 5 × 7 × 23, so it is divisible by 2.

What are the factors of 28980?

1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 14, 15, 18, 20, 21, 23, 28, 30, 35, 36, 42, 45, 46, 60, 63, 69, 70, 84, 90, 92, 105, 115, 126, 138, 140, 161, 180, 207, 210, 230, 252, 276, 315, 322, 345, 414, 420, 460, 483, 630, 644, 690, 805, 828, 966, 1035, 1260, 1380, 1449, 1610, 1932, 2070, 2415, 2898, 3220, 4140, 4830, 5796, 7245, 9660, 14490, 28980.

What is 28980 in binary?

111000100110100 (hexadecimal 7134, octal 70464).

What is the square root of 28980?

About 170.2351, exactly 6√805.

Is 28980 divisible by 3?

Yes. Its digits add up to 27, a multiple of 3.

What is special about the number 28980?

It is a composite number with 72 divisors.