81897029760 has 512 divisors, whose sum is σ = 325740280320. Its totient is φ = 17040015360.

The previous prime is 81897029749. The next prime is 81897029783. The reversal of 81897029760 is 6792079818.

It is a self number, because there is not a number n which added to its sum of digits gives 81897029760.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12751350 + ... + 12757770.

It is an arithmetic number, because the mean of its divisors is an integer number (636211485).

Almost surely, 2^81897029760 is an apocalyptic number.

81897029760 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 81897029760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162870140160).

81897029760 is an abundant number, since it is smaller than the sum of its proper divisors (243843250560).

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

81897029760 is a wasteful number, since it uses less digits than its factorization.

81897029760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6536 (or 6524 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 57.

The spelling of 81897029760 in words is "eighty-one billion, eight hundred ninety-seven million, twenty-nine thousand, seven hundred sixty".