81586560 has 128 divisors (see below), whose sum is σ = 283772160. Its totient is φ = 19773440.

The previous prime is 81586559. The next prime is 81586573. The reversal of 81586560 is 6568518.

It is a tau number, because it is divible by the number of its divisors (128).

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, 19189 + ... + 23051.

It is an arithmetic number, because the mean of its divisors is an integer number (2216970).

Almost surely, 2^81586560 is an apocalyptic number.

81586560 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81586560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141886080).

81586560 is an abundant number, since it is smaller than the sum of its proper divisors (202185600).

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

81586560 is a wasteful number, since it uses less digits than its factorization.

81586560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3896 (or 3884 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 39.

The square root of 81586560 is about 9032.5278853707. The cubic root of 81586560 is about 433.7167625344.

The spelling of 81586560 in words is "eighty-one million, five hundred eighty-six thousand, five hundred sixty".