81716817600 has 1008 divisors, whose sum is σ = 333190514720. Its totient is φ = 19707494400.

The previous prime is 81716817517. The next prime is 81716817617. The reversal of 81716817600 is 671861718.

It is a happy number.

81716817600 is a `hidden beast` number, since 8 + 17 + 16 + 8 + 17 + 600 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 143 ways as a sum of consecutive naturals, for example, 423403104 + ... + 423403296.

Almost surely, 2^81716817600 is an apocalyptic number.

81716817600 is a gapful number since it is divisible by the number (80) 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 81716817600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (166595257360).

81716817600 is an abundant number, since it is smaller than the sum of its proper divisors (251473697120).

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

81716817600 is a wasteful number, since it uses less digits than its factorization.

81716817600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258 (or 214 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 45.

The spelling of 81716817600 in words is "eighty-one billion, seven hundred sixteen million, eight hundred seventeen thousand, six hundred".