81936288 has 144 divisors (see below), whose sum is σ = 269680320. Its totient is φ = 23113728.

The previous prime is 81936269. The next prime is 81936293. The reversal of 81936288 is 88263918.

81936288 is a `hidden beast` number, since 8 + 19 + 3 + 628 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a nude number because it is divisible by every one of its digits.

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 23 ways as a sum of consecutive naturals, for example, 195343 + ... + 195761.

It is an arithmetic number, because the mean of its divisors is an integer number (1872780).

Almost surely, 2^81936288 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81936288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134840160).

81936288 is an abundant number, since it is smaller than the sum of its proper divisors (187744032).

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

81936288 is a wasteful number, since it uses less digits than its factorization.

81936288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 539 (or 528 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 81936288 is about 9051.8665478453. The cubic root of 81936288 is about 434.3356008845.

The spelling of 81936288 in words is "eighty-one million, nine hundred thirty-six thousand, two hundred eighty-eight".