81535584 has 96 divisors (see below), whose sum is σ = 233694720. Its totient is φ = 24740352.

The previous prime is 81535577. The next prime is 81535591. The reversal of 81535584 is 48553518.

It is an interprime number because it is at equal distance from previous prime (81535577) and next prime (81535591).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 98179 + ... + 99005.

It is an arithmetic number, because the mean of its divisors is an integer number (2434320).

Almost surely, 2^81535584 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 81535584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116847360).

81535584 is an abundant number, since it is smaller than the sum of its proper divisors (152159136).

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

81535584 is a wasteful number, since it uses less digits than its factorization.

81535584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 932 (or 924 counting only the distinct ones).

The product of its digits is 96000, while the sum is 39.

The square root of 81535584 is about 9029.7056430429. The cubic root of 81535584 is about 433.6264136994.

The spelling of 81535584 in words is "eighty-one million, five hundred thirty-five thousand, five hundred eighty-four".