845561 has 4 divisors (see below), whose sum is σ = 868452. Its totient is φ = 822672.

The previous prime is 845531. The next prime is 845567. The reversal of 845561 is 165548.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 462400 + 383161 = 680^2 + 619^2 .

It is a cyclic number.

It is not a de Polignac number, because 845561 - 2¹⁴ = 829177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (845567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11390 + ... + 11463.

It is an arithmetic number, because the mean of its divisors is an integer number (217113).

2⁸⁴⁵⁵⁶¹ is an apocalyptic number.

It is an amenable number.

845561 is a deficient number, since it is larger than the sum of its proper divisors (22891).

845561 is a wasteful number, since it uses less digits than its factorization.

845561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22890.

The product of its digits is 4800, while the sum is 29.

The square root of 845561 is about 919.5439086852. The cubic root of 845561 is about 94.5616368605.

The spelling of 845561 in words is "eight hundred forty-five thousand, five hundred sixty-one".