81910793184 has 576 divisors, whose sum is σ = 261894560256. Its totient is φ = 22302720000.

The previous prime is 81910793149. The next prime is 81910793197. The reversal of 81910793184 is 48139701918.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 542455509 + ... + 542455659.

It is an arithmetic number, because the mean of its divisors is an integer number (454678056).

Almost surely, 2^81910793184 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 81910793184, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130947280128).

81910793184 is an abundant number, since it is smaller than the sum of its proper divisors (179983767072).

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

81910793184 is a wasteful number, since it uses less digits than its factorization.

81910793184 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311 (or 292 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 51.

The spelling of 81910793184 in words is "eighty-one billion, nine hundred ten million, seven hundred ninety-three thousand, one hundred eighty-four".