The factors of 49 are 1, 7 and 49. The factors of a given number are those numbers that divide into it evenly leaving no remainder. One and the number itself, 49 in this case, are always factors.
The number 49 is a square, which means that a number multiplied by itself yields 49, and that number is seven. Seven is called the square root of 49. Seven is also a prime number, which means it is evenly divisible by only one and itself. The prime factorization of 49 therefore is 7 x 7 or 7^2. Prime factorization of a number involves finding the prime numbers that multiply together to yield that number.