Were Adolf Hitler and John von Neumann alive at the same time?
Yes. Adolf Hitler and John von Neumann were alive at the same time for 41 years, from 1903 to 1945.
Adolf Hitler was 14 when John von Neumann was born.
John von Neumann was 41 when Adolf Hitler died, aged 56.
John von Neumann
Hungarian and American mathematician and physicist
Born 28 December 1903 · died 8 February 1957, aged 53