Python Program for Find largest prime factor of a number

Given a positive integer \’n\'( 1 <= n <= 10^{15}). Find the largest prime factor of a number.

Input:6Output:3ExplanationPrime factor of 6 are- 2, 3 Largest of them is \'3\'Input:15Output:5

## Python3

`# Python3 code to find largest prime` `# factor of number` `import` `math` ` ` `# A function to find largest prime factor` `def` `maxPrimeFactors (n):` ` ` ` ` `# Initialize the maximum prime factor` ` ` `# variable with the lowest one` ` ` `maxPrime ` `=` `-` `1` ` ` ` ` `# Print the number of 2s that divide n` ` ` `while` `n ` `%` `2` `=` `=` `0` `:` ` ` `maxPrime ` `=` `2` ` ` `n >>` `=` `1` `# equivalent to n /= 2` ` ` ` ` `# n must be odd at this point, ` ` ` `# thus skip the even numbers and ` ` ` `# iterate only for odd integers` ` ` `for` `i ` `in` `range` `(` `3` `, ` `int` `(math.sqrt(n)) ` `+` `1` `, ` `2` `):` ` ` `while` `n ` `%` `i ` `=` `=` `0` `:` ` ` `maxPrime ` `=` `i` ` ` `n ` `=` `n ` `/` `i` ` ` ` ` `# This condition is to handle the ` ` ` `# case when n is a prime number ` ` ` `# greater than 2` ` ` `if` `n > ` `2` `:` ` ` `maxPrime ` `=` `n` ` ` ` ` `return` `int` `(maxPrime)` ` ` `# Driver code to test above function` `n ` `=` `15` `print` `(maxPrimeFactors(n))` ` ` `n ` `=` `25698751364526` `print` `(maxPrimeFactors(n))` ` ` `# This code is contributed by "Sharad_Bhardwaj".` |

**Output:**

5 328513

**Time complexity: ****Auxiliary space: **

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