81583842816 has 600 divisors, whose sum is σ = 298312078680. Its totient is φ = 22072393728.

The previous prime is 81583842793. The next prime is 81583842871. The reversal of 81583842816 is 61824838518.

81583842816 is a `hidden beast` number, since 8 + 1 + 583 + 8 + 42 + 8 + 16 = 666.

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

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 38609376 + ... + 38611488.

Almost surely, 2^81583842816 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 81583842816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149156039340).

81583842816 is an abundant number, since it is smaller than the sum of its proper divisors (216728235864).

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

81583842816 is a wasteful number, since it uses less digits than its factorization.

81583842816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2176 (or 2144 counting only the distinct ones).

The product of its digits is 2949120, while the sum is 54.

The spelling of 81583842816 in words is "eighty-one billion, five hundred eighty-three million, eight hundred forty-two thousand, eight hundred sixteen".