81905459277600 has 3456 divisors, whose sum is σ = 376794507608064. Its totient is φ = 16930529280000.

The previous prime is 81905459277559. The next prime is 81905459277673. The reversal of 81905459277600 is 677295450918.

81905459277600 is a `hidden beast` number, since 8 + 1 + 9 + 0 + 545 + 9 + 27 + 7 + 60 + 0 = 666.

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

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 575 ways as a sum of consecutive naturals, for example, 129802629285 + ... + 129802629915.

It is an arithmetic number, because the mean of its divisors is an integer number (109026188544).

Almost surely, 2^{81905459277600} is an apocalyptic number.

81905459277600 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 81905459277600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (188397253804032).

81905459277600 is an abundant number, since it is smaller than the sum of its proper divisors (294889048330464).

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

81905459277600 is a wasteful number, since it uses less digits than its factorization.

81905459277600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 902 (or 877 counting only the distinct ones).

The product of its (nonzero) digits is 38102400, while the sum is 63.

The spelling of 81905459277600 in words is "eighty-one trillion, nine hundred five billion, four hundred fifty-nine million, two hundred seventy-seven thousand, six hundred".