81899716896 has 288 divisors, whose sum is σ = 247863732480. Its totient is φ = 26589689856.

The previous prime is 81899716889. The next prime is 81899716991. The reversal of 81899716896 is 69861799818.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 101235340 + ... + 101236148.

It is an arithmetic number, because the mean of its divisors is an integer number (860637960).

Almost surely, 2^81899716896 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 81899716896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123931866240).

81899716896 is an abundant number, since it is smaller than the sum of its proper divisors (165964015584).

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

81899716896 is a wasteful number, since it uses less digits than its factorization.

81899716896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1158 (or 1138 counting only the distinct ones).

The product of its digits is 94058496, while the sum is 72.

The spelling of 81899716896 in words is "eighty-one billion, eight hundred ninety-nine million, seven hundred sixteen thousand, eight hundred ninety-six".