81818880 has 288 divisors, whose sum is σ = 309052800. Its totient is φ = 18186240.

The previous prime is 81818879. The next prime is 81818887. The reversal of 81818880 is 8881818.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81818887) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 549046 + ... + 549194.

It is an arithmetic number, because the mean of its divisors is an integer number (1073100).

Almost surely, 2^81818880 is an apocalyptic number.

81818880 is a gapful number since it is divisible by the number (80) 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 81818880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154526400).

81818880 is an abundant number, since it is smaller than the sum of its proper divisors (227233920).

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

81818880 is a wasteful number, since it uses less digits than its factorization.

81818880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 183 counting only the distinct ones).

The product of its (nonzero) digits is 32768, while the sum is 42.

The square root of 81818880 is about 9045.3789307027. The cubic root of 81818880 is about 434.1280459177.

The spelling of 81818880 in words is "eighty-one million, eight hundred eighteen thousand, eight hundred eighty".