81111888 has 240 divisors, whose sum is σ = 277750080. Its totient is φ = 22464000.

The previous prime is 81111887. The next prime is 81111911. The reversal of 81111888 is 88811118.

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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (81111887) 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 47 ways as a sum of consecutive naturals, for example, 803038 + ... + 803138.

It is an arithmetic number, because the mean of its divisors is an integer number (1157292).

Almost surely, 2^81111888 is an apocalyptic number.

81111888 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81111888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138875040).

81111888 is an abundant number, since it is smaller than the sum of its proper divisors (196638192).

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

81111888 is a wasteful number, since it uses less digits than its factorization.

81111888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 130 counting only the distinct ones).

The product of its digits is 4096, while the sum is 36.

The square root of 81111888 is about 9006.2138548893. The cubic root of 81111888 is about 432.8740021722.

It can be divided in two parts, 8111 and 1888, that added together give a palindrome (9999).

The spelling of 81111888 in words is "eighty-one million, one hundred eleven thousand, eight hundred eighty-eight".