81866741184 has 252 divisors, whose sum is σ = 240849531000. Its totient is φ = 26585100288.

The previous prime is 81866741147. The next prime is 81866741197. The reversal of 81866741184 is 48114766818.

It is a self number, because there is not a number n which added to its sum of digits gives 81866741184.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 457356007 + ... + 457356185.

Almost surely, 2^81866741184 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81866741184, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120424765500).

81866741184 is an abundant number, since it is smaller than the sum of its proper divisors (158982789816).

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

81866741184 is a wasteful number, since it uses less digits than its factorization.

81866741184 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 492 (or 406 counting only the distinct ones).

The product of its digits is 2064384, while the sum is 54.

The spelling of 81866741184 in words is "eighty-one billion, eight hundred sixty-six million, seven hundred forty-one thousand, one hundred eighty-four".