81333888 has 64 divisors (see below), whose sum is σ = 225460800. Its totient is φ = 25929728.

The previous prime is 81333883. The next prime is 81333907. The reversal of 81333888 is 88833318.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

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

It is not an unprimeable number, because it can be changed into a prime (81333883) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4228 + ... + 13436.

It is an arithmetic number, because the mean of its divisors is an integer number (3522825).

Almost surely, 2^81333888 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 81333888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112730400).

81333888 is an abundant number, since it is smaller than the sum of its proper divisors (144126912).

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

81333888 is a wasteful number, since it uses less digits than its factorization.

81333888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9249 (or 9237 counting only the distinct ones).

The product of its digits is 110592, while the sum is 42.

The square root of 81333888 is about 9018.5302571982. The cubic root of 81333888 is about 433.2685620481.

It can be divided in two parts, 8133 and 3888, that added together give a palindrome (12021).

The spelling of 81333888 in words is "eighty-one million, three hundred thirty-three thousand, eight hundred eighty-eight".