1812020 has 54 divisors (see below), whose sum is σ = 4531842. Its totient is φ = 606816.

The previous prime is 1811993. The next prime is 1812037. The reversal of 1812020 is 202181.

It can be written as a sum of positive squares in only one way, i.e., 1449616 + 362404 = 1204^2 + 602^2 .

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 1811986 and 1812004.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 42119 + ... + 42161.

It is an arithmetic number, because the mean of its divisors is an integer number (83923).

2^1812020 is an apocalyptic number.

1812020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1812020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2265921).

1812020 is an abundant number, since it is smaller than the sum of its proper divisors (2719822).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1812020 is a wasteful number, since it uses less digits than its factorization.

1812020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 57 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 1812020 is about 1346.1129224549. The cubic root of 1812020 is about 121.9142100444.

The spelling of 1812020 in words is "one million, eight hundred twelve thousand, twenty".