81580528 has 40 divisors (see below), whose sum is σ = 168091920. Its totient is φ = 38246400.

The previous prime is 81580519. The next prime is 81580537. The reversal of 81580528 is 82508518.

It is an interprime number because it is at equal distance from previous prime (81580519) and next prime (81580537).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29376 + ... + 32032.

It is an arithmetic number, because the mean of its divisors is an integer number (4202298).

Almost surely, 2^81580528 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 81580528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84045960).

81580528 is an abundant number, since it is smaller than the sum of its proper divisors (86511392).

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

81580528 is a wasteful number, since it uses less digits than its factorization.

81580528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2785 (or 2779 counting only the distinct ones).

The product of its (nonzero) digits is 25600, while the sum is 37.

The square root of 81580528 is about 9032.1939748878. The cubic root of 81580528 is about 433.7060735026.

The spelling of 81580528 in words is "eighty-one million, five hundred eighty thousand, five hundred twenty-eight".