Why the if statement responde is None and not a value?

I was doing code to get a value by evaluating an equation to a number

import math


def find_nb(m):
    d = -10
    for i in range(1000000):
        d += 1
        if (math.pow(d, 2)*(math.pow((d+1), 2))) == 4*m:
            return d

print(find_nb(4183059834009))
>> output 2022
print(find_nb(4183059834009))
>>output None

but instead of giving me a negative value it just sent None. How can I change that if the result is none to return a fix value