81800320 has 192 divisors, whose sum is σ = 243086400. Its totient is φ = 25712640.

The previous prime is 81800317. The next prime is 81800353. The reversal of 81800320 is 2300818.

It is a junction number, because it is equal to n+sod(n) for n = 81800291 and 81800300.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2638705 + ... + 2638735.

It is an arithmetic number, because the mean of its divisors is an integer number (1266075).

Almost surely, 2^81800320 is an apocalyptic number.

81800320 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 81800320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121543200).

81800320 is an abundant number, since it is smaller than the sum of its proper divisors (161286080).

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

81800320 is a wasteful number, since it uses less digits than its factorization.

81800320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 81800320 is about 9044.3529342900. The cubic root of 81800320 is about 434.0952172036.

The spelling of 81800320 in words is "eighty-one million, eight hundred thousand, three hundred twenty".