81580 has 12 divisors (see below), whose sum is σ = 171360. Its totient is φ = 32624.

The previous prime is 81569. The next prime is 81611. The reversal of 81580 is 8518.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2020 + ... + 2059.

It is an arithmetic number, because the mean of its divisors is an integer number (14280).

2⁸¹⁵⁸⁰ is an apocalyptic number.

It is an amenable number.

81580 is an abundant number, since it is smaller than the sum of its proper divisors (89780).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85680).

81580 is a wasteful number, since it uses less digits than its factorization.

81580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4088 (or 4086 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 81580 is about 285.6221279943. The cubic root of 81580 is about 43.3705137833.

The spelling of 81580 in words is "eighty-one thousand, five hundred eighty".