81113868 has 72 divisors (see below), whose sum is σ = 236854800. Its totient is φ = 23132160.

The previous prime is 81113863. The next prime is 81113873. The reversal of 81113868 is 86831118.

It is an interprime number because it is at equal distance from previous prime (81113863) and next prime (81113873).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81113863) 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 23 ways as a sum of consecutive naturals, for example, 708 + ... + 12756.

It is an arithmetic number, because the mean of its divisors is an integer number (3289650).

Almost surely, 2^81113868 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 81113868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118427400).

81113868 is an abundant number, since it is smaller than the sum of its proper divisors (155740932).

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

81113868 is a wasteful number, since it uses less digits than its factorization.

81113868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12087 (or 12082 counting only the distinct ones).

The product of its digits is 9216, while the sum is 36.

The square root of 81113868 is about 9006.3237783238. The cubic root of 81113868 is about 432.8775243996.

The spelling of 81113868 in words is "eighty-one million, one hundred thirteen thousand, eight hundred sixty-eight".