81384947280 has 960 divisors, whose sum is σ = 367824457728. Its totient is φ = 15633285120.

The previous prime is 81384947261. The next prime is 81384947321. The reversal of 81384947280 is 8274948318.

It is a happy number.

81384947280 is a `hidden beast` number, since 8 + 1 + 3 + 8 + 494 + 72 + 80 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 34527862 + ... + 34530218.

Almost surely, 2^81384947280 is an apocalyptic number.

81384947280 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 81384947280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (183912228864).

81384947280 is an abundant number, since it is smaller than the sum of its proper divisors (286439510448).

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

81384947280 is a wasteful number, since it uses less digits than its factorization.

81384947280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2444 (or 2435 counting only the distinct ones).

The product of its (nonzero) digits is 3096576, while the sum is 54.

The spelling of 81384947280 in words is "eighty-one billion, three hundred eighty-four million, nine hundred forty-seven thousand, two hundred eighty".