81804168 has 40 divisors (see below), whose sum is σ = 229129230. Its totient is φ = 27267840.

The previous prime is 81804137. The next prime is 81804179. The reversal of 81804168 is 86140818.

It can be written as a sum of positive squares in only one way, i.e., 80676324 + 1127844 = 8982^2 + 1062^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

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 9 ways as a sum of consecutive naturals, for example, 62473 + ... + 63768.

Almost surely, 2^81804168 is an apocalyptic number.

It is an amenable number.

81804168 is an abundant number, since it is smaller than the sum of its proper divisors (147325062).

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

81804168 is a wasteful number, since it uses less digits than its factorization.

81804168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126259 (or 126246 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 36.

The square root of 81804168 is about 9044.5656612134. The cubic root of 81804168 is about 434.1020239097.

The spelling of 81804168 in words is "eighty-one million, eight hundred four thousand, one hundred sixty-eight".