81983518344 has 576 divisors, whose sum is σ = 288860083200. Its totient is φ = 20541081600.

The previous prime is 81983518343. The next prime is 81983518349. The reversal of 81983518344 is 44381538918.

81983518344 is a `hidden beast` number, since 8 + 1 + 9 + 83 + 518 + 3 + 44 = 666.

It is not an unprimeable number, because it can be changed into a prime (81983518343) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 161067562 + ... + 161068070.

It is an arithmetic number, because the mean of its divisors is an integer number (501493200).

Almost surely, 2^81983518344 is an apocalyptic number.

81983518344 is a gapful number since it is divisible by the number (84) 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 81983518344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144430041600).

81983518344 is an abundant number, since it is smaller than the sum of its proper divisors (206876564856).

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

81983518344 is a wasteful number, since it uses less digits than its factorization.

81983518344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646 (or 626 counting only the distinct ones).

The product of its digits is 3317760, while the sum is 54.

The spelling of 81983518344 in words is "eighty-one billion, nine hundred eighty-three million, five hundred eighteen thousand, three hundred forty-four".