81447800 has 72 divisors (see below), whose sum is σ = 220309560. Its totient is φ = 27921600.

The previous prime is 81447797. The next prime is 81447811. The reversal of 81447800 is 874418.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 5645 + ... + 13955.

It is an arithmetic number, because the mean of its divisors is an integer number (3059855).

Almost surely, 2^81447800 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 81447800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110154780).

81447800 is an abundant number, since it is smaller than the sum of its proper divisors (138861760).

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

81447800 is a wasteful number, since it uses less digits than its factorization.

81447800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8341 (or 8325 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 81447800 is about 9024.8434889476. The cubic root of 81447800 is about 433.4707388056.

The spelling of 81447800 in words is "eighty-one million, four hundred forty-seven thousand, eight hundred".