81539065 has 8 divisors (see below), whose sum is σ = 97898688. Its totient is φ = 65196720.

The previous prime is 81539063. The next prime is 81539099. The reversal of 81539065 is 56093518.

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

It is not a de Polignac number, because 81539065 - 2¹ = 81539063 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81539063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11034 + ... + 16876.

It is an arithmetic number, because the mean of its divisors is an integer number (12237336).

Almost surely, 2^81539065 is an apocalyptic number.

It is an amenable number.

81539065 is a deficient number, since it is larger than the sum of its proper divisors (16359623).

81539065 is a wasteful number, since it uses less digits than its factorization.

81539065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8639.

The product of its (nonzero) digits is 32400, while the sum is 37.

The square root of 81539065 is about 9029.8983936698. The cubic root of 81539065 is about 433.6325845514.

The spelling of 81539065 in words is "eighty-one million, five hundred thirty-nine thousand, sixty-five".