420 is the natural number following 419 and preceding 421.

List of numbers — Integers << 0 100 200 300 400 500 600 700 800 900 >>
420
Cardinal	Four hundred and twenty
Ordinal	420th
Factorization	<math>2^2 \cdot 3 \cdot 5 \cdot 7<math>
Roman numeral	CDXX
Binary	110100100
Hexadecimal	1A4

It is the sum of four consecutive primes (101 + 103 + 107 + 109). When passed to the Mertens function, it returns 0. 420 is a pronic number, and the smallest number divisible by the numbers 1 to 7, and as a consequence of that it is a Harshad number in every base from 2 to 10 except base 5. It is a 141-gonal number.

Other fields

420 is also:

• 420 class is a class of double handed sailing vessels for young sailors to practice on before progressing to 470 class.
• The number 420, or time 4:20, has significance within drug culture, for more, see: 420 (drug culture).
• The year 420 BC, or AD 420

External links

• 420Sailing.org (http://www.420sailing.org/)