66 (sixty-six) is the natural number following 65 and preceding 67.

In mathematics

66 is a sphenic number,a semiperfect number, and a Erdős–Woods number.

In science

Astronomy

Physics

In computing

66 (more specifically 66.667) megahertz (MHz) is a common divisor for the front side bus (FSB) speed, overall central processing unit (CPU) speed, and base bus speed. On a Core 2 CPU, and a Core 2 motherboard, the FSB is 1066 MHz (~16 × 66 MHz), the memory speed is usually 666.67 MHz (~10 × 66 MHz), and the processor speed ranges from 1.86 gigahertz (GHz) (~66 MHz × 28) to 2.93 GHz (~66 MHz × 44), in 266 MHz (~66 MHz × 4) increments.

In motor vehicle transportation

In religion

In sports

In entertainment

Cinema

Years

Television

Video games

In other fields