81540558684 has 120 divisors (see below), whose sum is σ = 243064050768. Its totient is φ = 23613534720.

The previous prime is 81540558601. The next prime is 81540558691. The reversal of 81540558684 is 48685504518.

81540558684 is a `hidden beast` number, since 8 + 1 + 5 + 4 + 0 + 558 + 6 + 84 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 81540558684.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 497782 + ... + 640989.

Almost surely, 2^81540558684 is an apocalyptic number.

It is an amenable number.

81540558684 is an abundant number, since it is smaller than the sum of its proper divisors (161523492084).

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

81540558684 is a wasteful number, since it uses less digits than its factorization.

81540558684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1138817 (or 1138806 counting only the distinct ones).

The product of its (nonzero) digits is 6144000, while the sum is 54.

The spelling of 81540558684 in words is "eighty-one billion, five hundred forty million, five hundred fifty-eight thousand, six hundred eighty-four".