85178509 has 16 divisors (see below), whose sum is σ = 93837744. Its totient is φ = 76838400.

The previous prime is 85178503. The next prime is 85178521. The reversal of 85178509 is 90587158.

It can be written as a sum of positive squares in 8 ways, for example, as 39413284 + 45765225 = 6278^2 + 6765^2 .

It is a cyclic number.

It is not a de Polignac number, because 85178509 - 2⁹ = 85177997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85178503) 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, 184539 + ... + 184999.

It is an arithmetic number, because the mean of its divisors is an integer number (5864859).

Almost surely, 2^85178509 is an apocalyptic number.

It is an amenable number.

85178509 is a deficient number, since it is larger than the sum of its proper divisors (8659235).

85178509 is a wasteful number, since it uses less digits than its factorization.

85178509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 768.

The product of its (nonzero) digits is 100800, while the sum is 43.

The square root of 85178509 is about 9229.2203896104. The cubic root of 85178509 is about 439.9905455958.

The spelling of 85178509 in words is "eighty-five million, one hundred seventy-eight thousand, five hundred nine".