81389149934400 has 2016 divisors, whose sum is σ = 378880250112000. Its totient is φ = 16067406643200.

The previous prime is 81389149934381. The next prime is 81389149934461. The reversal of 81389149934400 is 443994198318.

81389149934400 is a `hidden beast` number, since 8 + 1 + 3 + 89 + 149 + 9 + 3 + 4 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (2016).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 3799846891 + ... + 3799868309.

It is an arithmetic number, because the mean of its divisors is an integer number (187936632000).

Almost surely, 2^{81389149934400} is an apocalyptic number.

81389149934400 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 81389149934400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (189440125056000).

81389149934400 is an abundant number, since it is smaller than the sum of its proper divisors (297491100177600).

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

81389149934400 is a wasteful number, since it uses less digits than its factorization.

81389149934400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21637 (or 21619 counting only the distinct ones).

The product of its (nonzero) digits is 26873856, while the sum is 63.

The spelling of 81389149934400 in words is "eighty-one trillion, three hundred eighty-nine billion, one hundred forty-nine million, nine hundred thirty-four thousand, four hundred".