If you do not have the AWS Alias Configured then you would use
https://Your_AWS_Account_ID.signin.aws.amazon.com/console/
if an alias is configure then
https://Your_Alias.signin.aws.amazon.com/console/
Apparently the URL for the AWS IAM Login is quite hard to remember. I have created this site to navigate to the respective IAM Console's Login page by just remembering the alias or the account number.