1800400 has 60 divisors (see below), whose sum is σ = 4951072. Its totient is φ = 616320.

The previous prime is 1800397. The next prime is 1800401. The reversal of 1800400 is 40081.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1800401) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 2479 + ... + 3121.

2^1800400 is an apocalyptic number.

1800400 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 1800400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2475536).

1800400 is an abundant number, since it is smaller than the sum of its proper divisors (3150672).

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

1800400 is a wasteful number, since it uses less digits than its factorization.

1800400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 668 (or 657 counting only the distinct ones).

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

The square root of 1800400 is about 1341.7898494176. The cubic root of 1800400 is about 121.6530499137.

Adding to 1800400 its reverse (40081), we get a palindrome (1840481).

The spelling of 1800400 in words is "one million, eight hundred thousand, four hundred".