280609 has 4 divisors (see below), whose sum is σ = 320704. Its totient is φ = 240516.

The previous prime is 280607. The next prime is 280613. The reversal of 280609 is 906082.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 280609 - 2¹ = 280607 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (280603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20037 + ... + 20050.

It is an arithmetic number, because the mean of its divisors is an integer number (80176).

2²⁸⁰⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

280609 is a deficient number, since it is larger than the sum of its proper divisors (40095).

280609 is an equidigital number, since it uses as much as digits as its factorization.

280609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40094.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 280609 is about 529.7254005615. The cubic root of 280609 is about 65.4687223197.

The spelling of 280609 in words is "two hundred eighty thousand, six hundred nine".