85644809 has 4 divisors (see below), whose sum is σ = 86476416. Its totient is φ = 84813204.

The previous prime is 85644803. The next prime is 85644829. The reversal of 85644809 is 90844658.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90844658 = 2 ⋅45422329.

It is a cyclic number.

It is not a de Polignac number, because 85644809 - 2⁸ = 85644553 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 85644809.

It is not an unprimeable number, because it can be changed into a prime (85644803) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 415649 + ... + 415854.

It is an arithmetic number, because the mean of its divisors is an integer number (21619104).

Almost surely, 2^85644809 is an apocalyptic number.

It is an amenable number.

85644809 is a deficient number, since it is larger than the sum of its proper divisors (831607).

85644809 is a wasteful number, since it uses less digits than its factorization.

85644809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 831606.

The product of its (nonzero) digits is 276480, while the sum is 44.

The square root of 85644809 is about 9254.4480656601. The cubic root of 85644809 is about 440.7919775511.

The spelling of 85644809 in words is "eighty-five million, six hundred forty-four thousand, eight hundred nine".