81311805580 has 24 divisors (see below), whose sum is σ = 170794784160. Its totient is φ = 32517104640.

The previous prime is 81311805571. The next prime is 81311805581. The reversal of 81311805580 is 8550811318.

It is a super-3 number, since 3×81311805580³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (81311805581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 388176 + ... + 559735.

It is an arithmetic number, because the mean of its divisors is an integer number (7116449340).

Almost surely, 2^81311805580 is an apocalyptic number.

It is an amenable number.

81311805580 is an abundant number, since it is smaller than the sum of its proper divisors (89482978580).

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

81311805580 is a wasteful number, since it uses less digits than its factorization.

81311805580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 952209 (or 952207 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 40.

The spelling of 81311805580 in words is "eighty-one billion, three hundred eleven million, eight hundred five thousand, five hundred eighty".