Failed to find signal in the USA

I have recently arrived in the US (in Lansing, MI) where I cannot find network signal of my Airtel number +91 9897640819. This number is important because in India I used this for official works (banking, documentation, service subscription, etc) and connecting with relatives (esp on WhatsApp). Is there any way I can merge this number with my new number in the US +1 (517) 481-0901? If not, is there any other way I can connect to home?