In my experience, no. Quite the opposite.

Lambdas can be cost effective for bursty loads, but if you can push sustained CPU utilization, as this example does, EC2 is cheaper.

For example, an ARM-based Lambda with 2 GB of RAM running for 1 hour is $0.09. An a1.medium is $0.025/hr on-demand or $0.0084/hr spot.

Part of this is that Lambda scales your CPU performance with your memory usage. So even if your code can run in 128 MB of RAM, there's no cost benefit to you if it's CPU-constrained, because it will run 16x slower than if you allocated it 2048 MB of RAM.