81506 has 8 divisors (see below), whose sum is σ = 123984. Its totient is φ = 40180.

The previous prime is 81463. The next prime is 81509. The reversal of 81506 is 60518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81506.

It is not an unprimeable number, because it can be changed into a prime (81509) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80 + ... + 411.

It is an arithmetic number, because the mean of its divisors is an integer number (15498).

2⁸¹⁵⁰⁶ is an apocalyptic number.

81506 is a deficient number, since it is larger than the sum of its proper divisors (42478).

81506 is a wasteful number, since it uses less digits than its factorization.

81506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 576.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 81506 is about 285.4925568207. The cubic root of 81506 is about 43.3573962344.

The spelling of 81506 in words is "eighty-one thousand, five hundred six".