81091296 has 216 divisors, whose sum is σ = 274496040. Its totient is φ = 22556160.

The previous prime is 81091291. The next prime is 81091303. The reversal of 81091296 is 69219018.

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

It is a self number, because there is not a number n which added to its sum of digits gives 81091296.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81091291) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 452935 + ... + 453113.

It is an arithmetic number, because the mean of its divisors is an integer number (1270815).

Almost surely, 2^81091296 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 81091296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137248020).

81091296 is an abundant number, since it is smaller than the sum of its proper divisors (193404744).

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

81091296 is a wasteful number, since it uses less digits than its factorization.

81091296 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230 (or 208 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 81091296 is about 9005.0705716280. The cubic root of 81091296 is about 432.8373676085.

The spelling of 81091296 in words is "eighty-one million, ninety-one thousand, two hundred ninety-six".