1820020 has 48 divisors (see below), whose sum is σ = 4164048. Its totient is φ = 665600.

The previous prime is 1820009. The next prime is 1820023. The reversal of 1820020 is 200281.

It can be written as a sum of positive squares in 8 ways, for example, as 394384 + 1425636 = 628^2 + 1194^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1820023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17970 + ... + 18070.

It is an arithmetic number, because the mean of its divisors is an integer number (86751).

2^1820020 is an apocalyptic number.

1820020 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 1820020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2082024).

1820020 is an abundant number, since it is smaller than the sum of its proper divisors (2344028).

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

1820020 is a wasteful number, since it uses less digits than its factorization.

1820020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 1820020 is about 1349.0811687960. The cubic root of 1820020 is about 122.0933621998.

The spelling of 1820020 in words is "one million, eight hundred twenty thousand, twenty".