81501 has 8 divisors (see below), whose sum is σ = 124224. Its totient is φ = 46560.

The previous prime is 81463. The next prime is 81509. The reversal of 81501 is 10518.

It is a happy number.

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

It is not a de Polignac number, because 81501 - 2⁷ = 81373 is a prime.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81501.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1920 + ... + 1961.

It is an arithmetic number, because the mean of its divisors is an integer number (15528).

2⁸¹⁵⁰¹ is an apocalyptic number.

It is an amenable number.

81501 is a deficient number, since it is larger than the sum of its proper divisors (42723).

81501 is a wasteful number, since it uses less digits than its factorization.

81501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3891.

The product of its (nonzero) digits is 40, while the sum is 15.

The square root of 81501 is about 285.4837998906. The cubic root of 81501 is about 43.3565096272.

The spelling of 81501 in words is "eighty-one thousand, five hundred one".