81097771538400 has 1728 divisors, whose sum is σ = 290369331173376. Its totient is φ = 19628863488000.

The previous prime is 81097771538339. The next prime is 81097771538411. The reversal of 81097771538400 is 483517779018.

81097771538400 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×81097771538400² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 448053986310 + ... + 448053986490.

It is an arithmetic number, because the mean of its divisors is an integer number (168037807392).

Almost surely, 2^{81097771538400} is an apocalyptic number.

81097771538400 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 81097771538400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145184665586688).

81097771538400 is an abundant number, since it is smaller than the sum of its proper divisors (209271559634976).

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

81097771538400 is a wasteful number, since it uses less digits than its factorization.

81097771538400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 445 (or 395 counting only the distinct ones).

The product of its (nonzero) digits is 11854080, while the sum is 60.

The spelling of 81097771538400 in words is "eighty-one trillion, ninety-seven billion, seven hundred seventy-one million, five hundred thirty-eight thousand, four hundred".