81305985024 has 336 divisors, whose sum is σ = 265133297520. Its totient is φ = 23781703680.

The previous prime is 81305984993. The next prime is 81305985029. The reversal of 81305985024 is 42058950318.

81305985024 is a `hidden beast` number, since 8 + 1 + 3 + 0 + 598 + 50 + 2 + 4 = 666.

It is a super-2 number, since 2×81305985024² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81305985029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23517504 + ... + 23520960.

It is an arithmetic number, because the mean of its divisors is an integer number (789087195).

Almost surely, 2^81305985024 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 81305985024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132566648760).

81305985024 is an abundant number, since it is smaller than the sum of its proper divisors (183827312496).

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

81305985024 is a wasteful number, since it uses less digits than its factorization.

81305985024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3529 (or 3502 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The spelling of 81305985024 in words is "eighty-one billion, three hundred five million, nine hundred eighty-five thousand, twenty-four".