• Curiously, 2020 is the smallest such that (20! - )/20 is prime.
2020 has 12
divisors (see below), whose sum is σ = 4284
Its totient is φ = 800
The previous prime is 2017. The next prime is 2027. The reversal of 2020 is 202.
2020 = T3 + T4 + ... +
It can be written as a sum of positive squares in 2 ways, for example, as 1444 + 576 = 38^2 + 24^2
It is a Harshad number since it is a multiple of its sum of digits (4).
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
2020 is an undulating number in base 10.
It is a plaindrome in base 11.
It is a nialpdrome in base 14.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (2027) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31 + ... + 70.
It is an arithmetic number, because the mean of its divisors is an integer number (357).
2020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.
It is an amenable number.
2020 is an abundant number, since it is smaller than the sum of its proper divisors (2264).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2142).
2020 is a wasteful number, since it uses less digits than its factorization.
2020 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 110 (or 108 counting only the distinct ones).
The product of its (nonzero) digits is 4, while the sum is 4.
The square root of 2020 is about 44.9444101085.
The cubic root of 2020 is about 12.6410686486.
Adding to 2020 its reverse (202), we get a palindrome (2222).
The spelling of 2020 in words is "two thousand, twenty", and thus it is an iban number.