81424584 has 48 divisors (see below), whose sum is σ = 222728220. Its totient is φ = 26870400.

The previous prime is 81424579. The next prime is 81424597. The reversal of 81424584 is 48542418.

It can be written as a sum of positive squares in 2 ways, for example, as 79602084 + 1822500 = 8922^2 + 1350^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1674 + ... + 12870.

Almost surely, 2^81424584 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 81424584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111364110).

81424584 is an abundant number, since it is smaller than the sum of its proper divisors (141303636).

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

81424584 is a wasteful number, since it uses less digits than its factorization.

81424584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11310 (or 11303 counting only the distinct ones).

The product of its digits is 40960, while the sum is 36.

The square root of 81424584 is about 9023.5571699857. The cubic root of 81424584 is about 433.4295491807.

The spelling of 81424584 in words is "eighty-one million, four hundred twenty-four thousand, five hundred eighty-four".