81588140 has 24 divisors (see below), whose sum is σ = 172056192. Its totient is φ = 32497920.

The previous prime is 81588139. The next prime is 81588163. The reversal of 81588140 is 4188518.

It is a self number, because there is not a number n which added to its sum of digits gives 81588140.

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 7 ways as a sum of consecutive naturals, for example, 3644 + ... + 13283.

It is an arithmetic number, because the mean of its divisors is an integer number (7169008).

Almost surely, 2^81588140 is an apocalyptic number.

It is an amenable number.

81588140 is an abundant number, since it is smaller than the sum of its proper divisors (90468052).

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

81588140 is a wasteful number, since it uses less digits than its factorization.

81588140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17177 (or 17175 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 35.

The square root of 81588140 is about 9032.6153466203. The cubic root of 81588140 is about 433.7195622931.

The spelling of 81588140 in words is "eighty-one million, five hundred eighty-eight thousand, one hundred forty".