280845 has 18 divisors (see below), whose sum is σ = 493038. Its totient is φ = 147888.

The previous prime is 280843. The next prime is 280859. The reversal of 280845 is 548082.

It can be written as a sum of positive squares in only one way, i.e., 224676 + 56169 = 474^2 + 237^2 .

It is not a de Polignac number, because 280845 - 2¹ = 280843 is a prime.

280845 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (280843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 3516 + ... + 3594.

It is an arithmetic number, because the mean of its divisors is an integer number (27391).

2²⁸⁰⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

280845 is a deficient number, since it is larger than the sum of its proper divisors (212193).

280845 is an equidigital number, since it uses as much as digits as its factorization.

280845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 27.

The square root of 280845 is about 529.9481106675. The cubic root of 280845 is about 65.4870708509.

The spelling of 280845 in words is "two hundred eighty thousand, eight hundred forty-five".