845609 has 4 divisors (see below), whose sum is σ = 848640. Its totient is φ = 842580.

The previous prime is 845599. The next prime is 845623. The reversal of 845609 is 906548.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-845609 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (845659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1049 + ... + 1670.

It is an arithmetic number, because the mean of its divisors is an integer number (212160).

2⁸⁴⁵⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

845609 is a deficient number, since it is larger than the sum of its proper divisors (3031).

845609 is a wasteful number, since it uses less digits than its factorization.

845609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3030.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 845609 is about 919.5700082104. The cubic root of 845609 is about 94.5634261549.

It can be divided in two parts, 845 and 609, that multiplied together give a triangular number (514605 = T₁₀₁₄).

The spelling of 845609 in words is "eight hundred forty-five thousand, six hundred nine".