845509 has 12 divisors (see below), whose sum is σ = 1007776. Its totient is φ = 694512.

The previous prime is 845491. The next prime is 845531. The reversal of 845509 is 905548.

It is not a de Polignac number, because 845509 - 2⁷ = 845381 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (845599) 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 11 ways as a sum of consecutive naturals, for example, 15927 + ... + 15979.

2⁸⁴⁵⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

845509 is a deficient number, since it is larger than the sum of its proper divisors (162267).

845509 is an equidigital number, since it uses as much as digits as its factorization.

845509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 845509 is about 919.5156333636. The cubic root of 845509 is about 94.5596983818.

The spelling of 845509 in words is "eight hundred forty-five thousand, five hundred nine".