Several apps cater to real estate investors by providing tools for managing tenants, rental properties, and payment systems. Here are some popular ones:

1. Cozy: Cozy offers a comprehensive platform for landlords to manage rental properties, screen tenants, collect rent payments, and handle maintenance requests. It also provides features for lease management and rental accounting.

2. Buildium: Buildium is a property management software designed for real estate investors, property managers, and homeowner associations. It offers features for tenant screening, lease management, rent collection, maintenance tracking, and financial reporting.

3. Rentec Direct: Rentec Direct is a property management software solution that helps landlords and property managers streamline rental property operations. It offers tools for tenant screening, online rent collection, expense tracking, and property maintenance.

4. RentRedi: RentRedi is a mobile-friendly property management app that simplifies landlord tasks such as tenant screening, lease signing, rent collection, and maintenance coordination. It also provides features for communication with tenants and document storage.

5. Landlord Studio: Landlord Studio is a rental property management app that offers features for tracking rental income and expenses, managing lease agreements, and generating financial reports. It also includes tools for tenant communication and rent reminders.

6. TenantCloud: TenantCloud is a cloud-based property management platform that helps landlords and property managers manage rental properties, screen tenants, collect rent payments, and handle maintenance requests. It also offers features for online lease signing and communication with tenants.

7. Avail: Avail is a rental property management platform that simplifies the process of finding tenants, screening applicants, and managing rental properties. It offers features for online rent collection, lease management, maintenance tracking, and financial reporting.

8. Rentigo: Rentigo is a property management app that offers tools for tenant screening, rent collection, maintenance requests, and communication with tenants. It also provides features for tracking rental income and expenses and generating financial reports.

9. Hemlane: Hemlane is a property management platform that helps landlords and property managers automate rental property tasks such as tenant screening, lease signing, rent collection, and maintenance coordination. It also offers features for communication with tenants and financial reporting.

10. Stessa: Stessa is a rental property management platform that offers features for tracking rental income and expenses, managing leases, and generating financial reports. It also provides tools for analyzing property performance and optimizing investment strategies.

These apps offer a range of features and pricing plans, so real estate investors can choose the one that best fits their needs and budget.