81536576 has 42 divisors (see below), whose sum is σ = 177862230. Its totient is φ = 37058560.

The previous prime is 81536513. The next prime is 81536599. The reversal of 81536576 is 67563518.

It can be written as a sum of positive squares in only one way, i.e., 77440000 + 4096576 = 8800^2 + 2024^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2480 + ... + 13008.

It is an arithmetic number, because the mean of its divisors is an integer number (4234815).

Almost surely, 2^81536576 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 81536576, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88931115).

81536576 is an abundant number, since it is smaller than the sum of its proper divisors (96325654).

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

81536576 is a wasteful number, since it uses less digits than its factorization.

81536576 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10563 (or 10542 counting only the distinct ones).

The product of its digits is 151200, while the sum is 41.

The square root of 81536576 is about 9029.7605726841. The cubic root of 81536576 is about 433.6281722594.

The spelling of 81536576 in words is "eighty-one million, five hundred thirty-six thousand, five hundred seventy-six".