420 (number)
420 (four hundred [and] twenty) is the natural number following 419 and preceding 421.
| ||||
|---|---|---|---|---|
| Cardinal | four hundred twenty | |||
| Ordinal | 420th (four hundred twentieth) | |||
| Factorization | 22 × 3 × 5 × 7 | |||
| Greek numeral | ΥΚ´ | |||
| Roman numeral | CDXX | |||
| Binary | 1101001002 | |||
| Ternary | 1201203 | |||
| Octal | 6448 | |||
| Duodecimal | 2B012 | |||
| Hexadecimal | 1A416 | |||
In mathematics
420 is:
- the sum of four consecutive primes (101 + 103 + 107 + 109).
- the sum of the first 20 positive even numbers.
- a zero of the Mertens function[1] and is sparsely totient.[2]
- a pronic number.[3]
- 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.
- a 141-gonal number.
- a Harshad number.
In other fields
- 420 is a slang term that refers to the consumption of cannabis. April 20th is commonly celebrated as a holiday dedicated to the drug, due to the numerical form of the day being 4/20.
- 420 is the country calling code for Czech Republic.
References
- "Sloane's A028442 : Numbers n such that Mertens' function is zero". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-02.
- "Sloane's A036913 : Sparsely totient numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-02.
- "Sloane's A002378 : Oblong (or promic, pronic, or heteromecic) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-02.
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