81187584 has 72 divisors (see below), whose sum is σ = 219746352. Its totient is φ = 26603520.

The previous prime is 81187571. The next prime is 81187619. The reversal of 81187584 is 48578118.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45982 + ... + 47714.

Almost surely, 2^81187584 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 81187584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109873176).

81187584 is an abundant number, since it is smaller than the sum of its proper divisors (138558768).

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

81187584 is a wasteful number, since it uses less digits than its factorization.

81187584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1813 (or 1799 counting only the distinct ones).

The product of its digits is 71680, while the sum is 42.

The square root of 81187584 is about 9010.4153067436. The cubic root of 81187584 is about 433.0086172229.

The spelling of 81187584 in words is "eighty-one million, one hundred eighty-seven thousand, five hundred eighty-four".