181800 has 72 divisors (see below), whose sum is σ = 616590. Its totient is φ = 48000.

The previous prime is 181789. The next prime is 181813. The reversal of 181800 is 8181.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 171396 + 10404 = 414^2 + 102^2 .

It is a tau number, because it is divible by the number of its divisors (72).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1750 + ... + 1850.

2¹⁸¹⁸⁰⁰ is an apocalyptic number.

181800 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 181800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (308295).

181800 is an abundant number, since it is smaller than the sum of its proper divisors (434790).

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

181800 is a wasteful number, since it uses less digits than its factorization.

181800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 181800 is about 426.3801121066. The cubic root of 181800 is about 56.6497450435.

Adding to 181800 its reverse (8181), we get a palindrome (189981).

It can be divided in two parts, 18 and 1800, that multiplied together give a square (32400 = 180²).

The spelling of 181800 in words is "one hundred eighty-one thousand, eight hundred".