1800000 has 126 divisors (see below), whose sum is σ = 6448806. Its totient is φ = 480000.

The previous prime is 1799999. The next prime is 1800017. The reversal of 1800000 is 81.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 3 ways, for example, as 831744 + 968256 = 912^2 + 984^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

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, 359998 + ... + 360002.

It is an arithmetic number, because the mean of its divisors is an integer number (51181).

2^1800000 is an apocalyptic number.

1800000 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 1800000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3224403).

1800000 is an abundant number, since it is smaller than the sum of its proper divisors (4648806).

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

1800000 is an frugal number, since it uses more digits than its factorization.

1800000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43 (or 10 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1800000 is about 1341.6407864999. The cubic root of 1800000 is about 121.6440399115.

Adding to 1800000 its reverse (81), we get a palindrome (1800081).

The spelling of 1800000 in words is "one million, eight hundred thousand".