280945 has 16 divisors (see below), whose sum is σ = 403200. Its totient is φ = 183744.

The previous prime is 280939. The next prime is 280949. The reversal of 280945 is 549082.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 280945 - 2⁵ = 280913 is a prime.

280945 is a modest number, since divided by 945 gives 280 as remainder.

It is not an unprimeable number, because it can be changed into a prime (280949) 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, 631 + ... + 979.

It is an arithmetic number, because the mean of its divisors is an integer number (25200).

2²⁸⁰⁹⁴⁵ is an apocalyptic number.

It is an amenable number.

280945 is a deficient number, since it is larger than the sum of its proper divisors (122255).

280945 is a wasteful number, since it uses less digits than its factorization.

280945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 280945 is about 530.0424511301. The cubic root of 280945 is about 65.4948425518.

It can be divided in two parts, 280 and 945, that added together give a triangular number (1225 = T₄₉).

The spelling of 280945 in words is "two hundred eighty thousand, nine hundred forty-five".