
    Given the total number of learning activities completed by a student in a semester, calculate the sum of all possible checkpoint intervals (where each interval must evenly divide into the total activities) to determine optimal progress monitoring frequency. For example, if a student has completed 12 activities, finding the sum of all numbers that evenly divide into 12 would help establish balanced checkpoints for progress review.
    

    
def sum_div(number):
    """
    Given the total number of learning activities completed by a student in a semester, calculate the sum of all possible checkpoint intervals (where each interval must evenly divide into the total activities) to determine optimal progress monitoring frequency. For example, if a student has completed 12 activities, finding the sum of all numbers that evenly divide into 12 would help establish balanced checkpoints for progress review.
    

    """
def sum_div(number):
    """
    Given the total number of learning activities completed by a student in a semester, calculate the sum of all possible checkpoint intervals (where each interval must evenly divide into the total activities) to determine optimal progress monitoring frequency. For example, if a student has completed 12 activities, finding the sum of all numbers that evenly divide into 12 would help establish balanced checkpoints for progress review.
    

    """
    divisors = [1]
    for i in range(2, number):
        if number % i == 0:
            divisors.append(i)
    return sum(divisors)