81144800 has 72 divisors (see below), whose sum is σ = 216126792. Its totient is φ = 29504000.

The previous prime is 81144793. The next prime is 81144809. The reversal of 81144800 is 844118.

It is a self number, because there is not a number n which added to its sum of digits gives 81144800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81144809) 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 11 ways as a sum of consecutive naturals, for example, 4190 + ... + 13410.

It is an arithmetic number, because the mean of its divisors is an integer number (3001761).

Almost surely, 2^81144800 is an apocalyptic number.

81144800 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 81144800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108063396).

81144800 is an abundant number, since it is smaller than the sum of its proper divisors (134981992).

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

81144800 is a wasteful number, since it uses less digits than its factorization.

81144800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9252 (or 9239 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 81144800 is about 9008.0408524829. The cubic root of 81144800 is about 432.9325419786.

Adding to 81144800 its reverse (844118), we get a palindrome (81988918).

The spelling of 81144800 in words is "eighty-one million, one hundred forty-four thousand, eight hundred".