The first large scale electronic computer which became operational in 1946 and contained approximately 18000 vacuum tubes and could perform 300 multiplications per second was known as

ENIAC (Electronic Numerical Integrator And Computer) was the world’s first general-purpose computer. ENIAC was designed and built for the United States Army to calculate artillery firing tables. However, it was ENIAC’s power and general-purpose programmability that excited the public’s imagination. When it was announced in 1946, ENIAC was referred to in the media as a “giant brain.”

Source : techtarget.com