420 (number)

In mathematics

• the sum of four consecutive primes.
• the sum of the first 20 positive even numbers.
• a zero of the Mertens function and is sparsely totient.
• a pronic number.
• 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 code-term that refers to the consumption of cannabis.
• 420 is the country calling code for Czech Republic.