A Prime number has only 2 factors which are 1 and itself. Composite numbers are everything else except 1 and 0. 1 and 0 are neither prime, nor composite. 645 is composite.
It is composite.
645 rounded to the nearest hundred is 600.
No
645 is a 3-digit number. A single digit in a number can have a place value. A number with several digits cannot.
An even number can be divided by 2 evenly. An odd number will have a remainder of 1 when divided by 2. 645 is an odd number.
645129 x 543 x 5 x 3
606
3665
866-645-y100
No. It does not read backwards the same as it does forwards.
By comparing the first three digits of the Social Security Number you can identify the state in which the subject resided at the time the number was issued.627-645 Texas449-467 Texas
Pokemon number 645. Please see related link