81415584 has 192 divisors, whose sum is σ = 263450880. Its totient is φ = 24330240.

The previous prime is 81415573. The next prime is 81415591. The reversal of 81415584 is 48551418.

It is a super-2 number, since 2×81415584² = 13256994636122112, which contains 22 as substring.

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 31 ways as a sum of consecutive naturals, for example, 337704 + ... + 337944.

It is an arithmetic number, because the mean of its divisors is an integer number (1372140).

Almost surely, 2^81415584 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 81415584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131725440).

81415584 is an abundant number, since it is smaller than the sum of its proper divisors (182035296).

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

81415584 is a wasteful number, since it uses less digits than its factorization.

81415584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300 (or 286 counting only the distinct ones).

The product of its digits is 25600, while the sum is 36.

The square root of 81415584 is about 9023.0584615196. The cubic root of 81415584 is about 433.4135793532.

The spelling of 81415584 in words is "eighty-one million, four hundred fifteen thousand, five hundred eighty-four".