81831613500 has 768 divisors, whose sum is σ = 331688448000. Its totient is φ = 16957900800.

The previous prime is 81831613499. The next prime is 81831613529. The reversal of 81831613500 is 531613818.

81831613500 is a `hidden beast` number, since 8 + 1 + 8 + 31 + 613 + 5 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 255 ways as a sum of consecutive naturals, for example, 72480936 + ... + 72482064.

It is an arithmetic number, because the mean of its divisors is an integer number (431886000).

Almost surely, 2^81831613500 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 81831613500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165844224000).

81831613500 is an abundant number, since it is smaller than the sum of its proper divisors (249856834500).

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

81831613500 is a wasteful number, since it uses less digits than its factorization.

81831613500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1236 (or 1218 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 81831613500 in words is "eighty-one billion, eight hundred thirty-one million, six hundred thirteen thousand, five hundred".