420 (number)

← 419 420 421 →
List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	four hundred twenty
Ordinal	420th (four hundred and twentieth)
Factorization	2^2× 3 × 5 × 7
Roman numeral	CDXX
Binary	1101001002
Ternary	1201203
Quaternary	122104
Quinary	31405
Senary	15406
Octal	6448
Duodecimal	2B012
Hexadecimal	1A416
Vigesimal	11020
Base 36	BO36

420 is the natural number following 419 and preceding 421.

420 is the sum of four consecutive primes (101 + 103 + 107 + 109). 420 is a zero of the Mertens function^[1] and is sparsely totient.^[2] It is a pronic number,^[3] 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.

References

1. "Sloane's A028442 : Numbers n such that Mertens' function is zero". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-02.
2. "Sloane's A036913 : Sparsely totient numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-02.
3. "Sloane's A002378 : Oblong (or promic, pronic, or heteromecic) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-02.