81539133 has 16 divisors (see below), whose sum is σ = 117243840. Its totient is φ = 50108544.

The previous prime is 81539099. The next prime is 81539141. The reversal of 81539133 is 33193518.

It is not a de Polignac number, because 81539133 - 2¹⁶ = 81473597 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81539094 and 81539103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81539173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55158 + ... + 56616.

It is an arithmetic number, because the mean of its divisors is an integer number (7327740).

Almost surely, 2^81539133 is an apocalyptic number.

It is an amenable number.

81539133 is a deficient number, since it is larger than the sum of its proper divisors (35704707).

81539133 is a wasteful number, since it uses less digits than its factorization.

81539133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2908.

The product of its digits is 9720, while the sum is 33.

The square root of 81539133 is about 9029.9021589384. The cubic root of 81539133 is about 433.6327050948.

The spelling of 81539133 in words is "eighty-one million, five hundred thirty-nine thousand, one hundred thirty-three".