280665 has 56 divisors (see below), whose sum is σ = 629568. Its totient is φ = 116640.

The previous prime is 280639. The next prime is 280673. The reversal of 280665 is 566082.

It is not a de Polignac number, because 280665 - 2⁷ = 280537 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a d-powerful number, because it can be written as 2² + 8² + 6² + 0 + 6⁷ + 5⁴ .

280665 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 280665.

It is an unprimeable number.

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 55 ways as a sum of consecutive naturals, for example, 25510 + ... + 25520.

2²⁸⁰⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

280665 is an abundant number, since it is smaller than the sum of its proper divisors (348903).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

280665 is an equidigital number, since it uses as much as digits as its factorization.

280665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41 (or 26 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 280665 is about 529.7782554994. The cubic root of 280665 is about 65.4730771391.

The spelling of 280665 in words is "two hundred eighty thousand, six hundred sixty-five".