81440169757688 has 32 divisors (see below), whose sum is σ = 180144154306560. Its totient is φ = 33777028931040.

The previous prime is 81440169757651. The next prime is 81440169757693. The reversal of 81440169757688 is 88675796104418.

It is a super-2 number, since 2×81440169757688² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23456268356 + ... + 23456271827.

It is an arithmetic number, because the mean of its divisors is an integer number (5629504822080).

Almost surely, 2^{81440169757688} is an apocalyptic number.

It is an amenable number.

81440169757688 is an abundant number, since it is smaller than the sum of its proper divisors (98703984548872).

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

81440169757688 is a wasteful number, since it uses less digits than its factorization.

81440169757688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46912540227 (or 46912540223 counting only the distinct ones).

The product of its (nonzero) digits is 650280960, while the sum is 74.

The spelling of 81440169757688 in words is "eighty-one trillion, four hundred forty billion, one hundred sixty-nine million, seven hundred fifty-seven thousand, six hundred eighty-eight".