642 = 2 x 3 x 107.
642 is a sphenic number because it the product of three distinct primes.
642 is the smallest number with the property that its first six multiples contain the digit 2: 642, 1284, 1926, 2568, 3210, 3852.
642 is 22002 in base 4, 1202 in base 8, and 456 in base 12.
642 Clara is an asteroid orbiting the Sun.
