81081750435840 has 6912 divisors, whose sum is σ = 405604132577280. Its totient is φ = 15135355699200.

The previous prime is 81081750435839. The next prime is 81081750435859. The reversal of 81081750435840 is 4853405718018.

81081750435840 is a `hidden beast` number, since 8 + 1 + 0 + 8 + 1 + 7 + 50 + 4 + 3 + 584 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (6912).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 575 ways as a sum of consecutive naturals, for example, 1110708910044 + ... + 1110708910116.

It is an arithmetic number, because the mean of its divisors is an integer number (58681153440).

Almost surely, 2^{81081750435840} is an apocalyptic number.

81081750435840 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 81081750435840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (202802066288640).

81081750435840 is an abundant number, since it is smaller than the sum of its proper divisors (324522382141440).

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

81081750435840 is a wasteful number, since it uses less digits than its factorization.

81081750435840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 149 counting only the distinct ones).

The product of its (nonzero) digits is 4300800, while the sum is 54.

The spelling of 81081750435840 in words is "eighty-one trillion, eighty-one billion, seven hundred fifty million, four hundred thirty-five thousand, eight hundred forty".