81015 has 16 divisors (see below), whose sum is σ = 141696. Its totient is φ = 39200.

The previous prime is 81013. The next prime is 81017. The reversal of 81015 is 51018.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81013) and next prime (81017).

It is not a de Polignac number, because 81015 - 2¹ = 81013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a junction number, because it is equal to n+sod(n) for n = 80985 and 81003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81013) 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 15 ways as a sum of consecutive naturals, for example, 81 + ... + 410.

It is an arithmetic number, because the mean of its divisors is an integer number (8856).

2⁸¹⁰¹⁵ is an apocalyptic number.

81015 is a deficient number, since it is larger than the sum of its proper divisors (60681).

81015 is a wasteful number, since it uses less digits than its factorization.

81015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510.

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

The square root of 81015 is about 284.6313405091. The cubic root of 81015 is about 43.2701577769.

The spelling of 81015 in words is "eighty-one thousand, fifteen".