81445584 has 120 divisors (see below), whose sum is σ = 238144480. Its totient is φ = 23950080.

The previous prime is 81445579. The next prime is 81445597. The reversal of 81445584 is 48554418.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 214707 + ... + 215085.

Almost surely, 2^81445584 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 81445584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119072240).

81445584 is an abundant number, since it is smaller than the sum of its proper divisors (156698896).

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

81445584 is a wasteful number, since it uses less digits than its factorization.

81445584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449 (or 432 counting only the distinct ones).

The product of its digits is 102400, while the sum is 39.

The square root of 81445584 is about 9024.7207159003. The cubic root of 81445584 is about 433.4668075356.

The spelling of 81445584 in words is "eighty-one million, four hundred forty-five thousand, five hundred eighty-four".