81340541688 has 128 divisors (see below), whose sum is σ = 233813952000. Its totient is φ = 23099281920.

The previous prime is 81340541663. The next prime is 81340541707. The reversal of 81340541688 is 88614504318.

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 31 ways as a sum of consecutive naturals, for example, 28429378 + ... + 28432238.

It is an arithmetic number, because the mean of its divisors is an integer number (1826671500).

Almost surely, 2^81340541688 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 81340541688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116906976000).

81340541688 is an abundant number, since it is smaller than the sum of its proper divisors (152473410312).

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

81340541688 is a wasteful number, since it uses less digits than its factorization.

81340541688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3845 (or 3841 counting only the distinct ones).

The product of its (nonzero) digits is 737280, while the sum is 48.

The spelling of 81340541688 in words is "eighty-one billion, three hundred forty million, five hundred forty-one thousand, six hundred eighty-eight".