81811296 has 192 divisors, whose sum is σ = 277724160. Its totient is φ = 23234688.

The previous prime is 81811271. The next prime is 81811297. The reversal of 81811296 is 69211818.

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

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

It is a self number, because there is not a number n which added to its sum of digits gives 81811296.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81811297) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 489805 + ... + 489971.

It is an arithmetic number, because the mean of its divisors is an integer number (1446480).

Almost surely, 2^81811296 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 81811296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138862080).

81811296 is an abundant number, since it is smaller than the sum of its proper divisors (195912864).

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

81811296 is an equidigital number, since it uses as much as digits as its factorization.

81811296 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205 (or 179 counting only the distinct ones).

The product of its digits is 6912, while the sum is 36.

The square root of 81811296 is about 9044.9597014028. The cubic root of 81811296 is about 434.1146320258.

The spelling of 81811296 in words is "eighty-one million, eight hundred eleven thousand, two hundred ninety-six".