1820520 has 96 divisors (see below), whose sum is σ = 6388200. Its totient is φ = 446976.

The previous prime is 1820509. The next prime is 1820521. The reversal of 1820520 is 250281.

It can be written as a sum of positive squares in 4 ways, for example, as 887364 + 933156 = 942^2 + 966^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 1820493 and 1820502.

It is not an unprimeable number, because it can be changed into a prime (1820521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4486 + ... + 4874.

2^1820520 is an apocalyptic number.

1820520 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 1820520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3194100).

1820520 is an abundant number, since it is smaller than the sum of its proper divisors (4567680).

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

1820520 is a wasteful number, since it uses less digits than its factorization.

1820520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419 (or 412 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 1820520 is about 1349.2664673814. The cubic root of 1820520 is about 122.1045417641.

It can be divided in two parts, 18205 and 20, that added together give a square (18225 = 135²).

The spelling of 1820520 in words is "one million, eight hundred twenty thousand, five hundred twenty".