85717809 has 6 divisors (see below), whose sum is σ = 123814626. Its totient is φ = 57145200.

The previous prime is 85717787. The next prime is 85717813. The reversal of 85717809 is 90871758.

85717809 is a `hidden beast` number, since 8 + 571 + 78 + 0 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 63250209 + 22467600 = 7953^2 + 4740^2 .

It is not a de Polignac number, because 85717809 - 2²¹ = 83620657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (85717889) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4762092 + ... + 4762109.

It is an arithmetic number, because the mean of its divisors is an integer number (20635771).

Almost surely, 2^85717809 is an apocalyptic number.

It is an amenable number.

85717809 is a deficient number, since it is larger than the sum of its proper divisors (38096817).

85717809 is a wasteful number, since it uses less digits than its factorization.

85717809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9524207 (or 9524204 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 45.

The square root of 85717809 is about 9258.3912749462. The cubic root of 85717809 is about 440.9171794430.

The spelling of 85717809 in words is "eighty-five million, seven hundred seventeen thousand, eight hundred nine".