In case you do not have an AWS Alias Configured then you will have to use: https://your_aws_account_id.signin.aws.amazon.com/console/
If it is configured then: https://Your_Alias.signin.aws.amazon.com/console/
Apparently, URL for this AWS IAM Login is quite hard to remember. I have already created this site so as to navigate to the respective IAM Console Login page by just remembering the account number.
Check out this screenshot I am adding below: