81986755984 has 160 divisors (see below), whose sum is σ = 199043260416. Its totient is φ = 31903303680.

The previous prime is 81986755973. The next prime is 81986756011. The reversal of 81986755984 is 48955768918.

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 31 ways as a sum of consecutive naturals, for example, 20479327 + ... + 20483329.

Almost surely, 2^81986755984 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 81986755984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99521630208).

81986755984 is an abundant number, since it is smaller than the sum of its proper divisors (117056504432).

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

81986755984 is a wasteful number, since it uses less digits than its factorization.

81986755984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4413 (or 4407 counting only the distinct ones).

The product of its digits is 174182400, while the sum is 70.

The spelling of 81986755984 in words is "eighty-one billion, nine hundred eighty-six million, seven hundred fifty-five thousand, nine hundred eighty-four".