81388888 has 64 divisors (see below), whose sum is σ = 181739520. Its totient is φ = 33436800.

The previous prime is 81388871. The next prime is 81388889. The reversal of 81388888 is 88888318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81388889) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 300193 + ... + 300463.

It is an arithmetic number, because the mean of its divisors is an integer number (2839680).

Almost surely, 2^81388888 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 81388888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90869760).

81388888 is an abundant number, since it is smaller than the sum of its proper divisors (100350632).

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

81388888 is a wasteful number, since it uses less digits than its factorization.

81388888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488 (or 484 counting only the distinct ones).

The product of its digits is 786432, while the sum is 52.

The square root of 81388888 is about 9021.5790192183. The cubic root of 81388888 is about 433.3662023720.

The spelling of 81388888 in words is "eighty-one million, three hundred eighty-eight thousand, eight hundred eighty-eight".