181800400 has 30 divisors (see below), whose sum is σ = 436776422. Its totient is φ = 72720000.

The previous prime is 181800323. The next prime is 181800419. The reversal of 181800400 is 4008181.

It can be written as a sum of positive squares in 3 ways, for example, as 61591104 + 120209296 = 7848^2 + 10964^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 226851 + ... + 227650.

Almost surely, 2^181800400 is an apocalyptic number.

181800400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

181800400 is an abundant number, since it is smaller than the sum of its proper divisors (254976022).

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

181800400 is a wasteful number, since it uses less digits than its factorization.

181800400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454519 (or 454508 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 181800400 is about 13483.3378656770. The cubic root of 181800400 is about 566.4978659081.

Adding to 181800400 its reverse (4008181), we get a palindrome (185808581).

The spelling of 181800400 in words is "one hundred eighty-one million, eight hundred thousand, four hundred".