How to generate a random product_id int to MySQL when adding a new product via Django Admin

I'm trying to add a "product_id" alongside new products to a MySQL database for use in an ecommerce website running Django. I then want to use these product_id values to be searchable from within the eCommerce site. For this reason they only need to be 5 characters long.

The product class in models.py looks like this:

from django.utils.crypto import get_random_string

class Product(models.Model):
    title = models.CharField(max_length=255)
    slug = models.SlugField(max_length=255)
    category = models.ForeignKey(Category, related_name='products', on_delete=models.CASCADE)
    product_id = models.IntegerField(get_random_string(5, 1234567890))  # Max length 5, numerals only
    description = models.TextField(blank=True, null=True)
    price = models.FloatField()

When trying to migrate the models to the MySQL server I get:

File "C:\Users\user\Desktop\ecommerce\apps\store\models.py", line 18, in <module>
   class Product(models.Model):
 File "C:\Users\user\Desktop\ecommerce\apps\store\models.py", line 22, in Product
   product_id = models.IntegerField(get_random_string(5, 1234567890))  # Create a random numeric id for each product
 File "C:\Users\user\Desktop\ecommerce\venv\lib\site-packages\django\utils\crypto.py", line 74, in get_random_string
   return ''.join(secrets.choice(allowed_chars) for i in range(length))
 File "C:\Users\user\Desktop\ecommerce\venv\lib\site-packages\django\utils\crypto.py", line 74, in <genexpr>
   return ''.join(secrets.choice(allowed_chars) for i in range(length))
 File "C:\Users\user\AppData\Local\Programs\Python\Python38\lib\random.py", line 288, in choice
   i = self._randbelow(len(seq))
TypeError: object of type 'int' has no len()

As I understand I should be able to set the length of an integer and set it as a numeric id to be stored each time a new product is created in the database.

My apologies if this question is stupid, but this is my very first question here and I searched and could not find a solution for this.