420 (four hundred [and] twenty) is the natural number following 419 and preceding 421.
In mathematics 420 is a zero of the Mertens function, a sparsely totient number, a pronic number, a balanced number, a largely composite number, a unitary harmonic number, an infinitary harmonic number. and a cluster prime.
420 is the number of minimal covers on 7 objects with 6 members.
Divisors The divisors of 420 is 1, 2, 3, 4, 5, 6, 7, 10, 12, 14, 15, 20, 21, 28, 30, 35, 42, 60, 70, 84, 105, 140, 210, and 420. Because the first seven divisors is going from 1 to 7, it is the smallest number that is divisible by 1 through 7.
In other fields 420 (pronounced four-twenty) is a cannabis culture slang for cannabis consumption.
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