845 has 6 divisors (see below), whose sum is σ = 1098. Its totient is φ = 624.

The previous prime is 839. The next prime is 853. The reversal of 845 is 548.

845 is nontrivially palindromic in base 12.

It can be written as a sum of positive squares in 3 ways, for example, as 4 + 841 = 2^2 + 29^2 .

It is not a de Polignac number, because 845 - 2⁴ = 829 is a prime.

It is a magnanimous number.

It is a Duffinian number.

845 is an undulating number in base 8 and base 12.

It is a plaindrome in base 9, base 14 and base 16.

It is a nialpdrome in base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 845.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 59 + ... + 71.

It is an arithmetic number, because the mean of its divisors is an integer number (183).

It is an amenable number.

845 is a deficient number, since it is larger than the sum of its proper divisors (253).

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

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

The sum of its prime factors is 31 (or 18 counting only the distinct ones).

The product of its digits is 160, while the sum is 17.

The square root of 845 is about 29.0688837075. The cubic root of 845 is about 9.4540719460.

Subtracting from 845 its sum of digits (17), we obtain a palindrome (828).

Multiplying 845 by its sum of digits (17), we get a triangular number (14365 = T₁₆₉).

The spelling of 845 in words is "eight hundred forty-five", and thus it is an aban number.