81609085 has 16 divisors (see below), whose sum is σ = 103642560. Its totient is φ = 61516800.

The previous prime is 81609079. The next prime is 81609089. The reversal of 81609085 is 58090618.

It is not a de Polignac number, because 81609085 - 2¹⁵ = 81576317 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81609089) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16110 + ... + 20560.

It is an arithmetic number, because the mean of its divisors is an integer number (6477660).

Almost surely, 2^81609085 is an apocalyptic number.

It is an amenable number.

81609085 is a deficient number, since it is larger than the sum of its proper divisors (22033475).

81609085 is a wasteful number, since it uses less digits than its factorization.

81609085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4668.

The product of its (nonzero) digits is 17280, while the sum is 37.

The square root of 81609085 is about 9033.7746817153. The cubic root of 81609085 is about 433.7566734018.

The spelling of 81609085 in words is "eighty-one million, six hundred nine thousand, eighty-five".