280545 has 16 divisors (see below), whose sum is σ = 457920. Its totient is φ = 146624.

The previous prime is 280541. The next prime is 280547. The reversal of 280545 is 545082.

It is a cyclic number.

It is not a de Polignac number, because 280545 - 2² = 280541 is a prime.

It is a Curzon number.

280545 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 280545.

It is not an unprimeable number, because it can be changed into a prime (280541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 727 + ... + 1043.

It is an arithmetic number, because the mean of its divisors is an integer number (28620).

2²⁸⁰⁵⁴⁵ is an apocalyptic number.

It is an amenable number.

280545 is a deficient number, since it is larger than the sum of its proper divisors (177375).

280545 is a wasteful number, since it uses less digits than its factorization.

280545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384.

The product of its (nonzero) digits is 1600, while the sum is 24.

The square root of 280545 is about 529.6649884597. The cubic root of 280545 is about 65.4637446737.

It can be divided in two parts, 2805 and 45, that added together give a triangular number (2850 = T₇₅).

The spelling of 280545 in words is "two hundred eighty thousand, five hundred forty-five".