281209 has 4 divisors (see below), whose sum is σ = 282960. Its totient is φ = 279460.

The previous prime is 281207. The next prime is 281227. The reversal of 281209 is 902182.

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 281209 - 2¹ = 281207 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 281209.

It is not an unprimeable number, because it can be changed into a prime (281207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 607 + ... + 964.

It is an arithmetic number, because the mean of its divisors is an integer number (70740).

2²⁸¹²⁰⁹ is an apocalyptic number.

It is an amenable number.

281209 is a deficient number, since it is larger than the sum of its proper divisors (1751).

281209 is a wasteful number, since it uses less digits than its factorization.

281209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1750.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 281209 is about 530.2914293103. The cubic root of 281209 is about 65.5153509850.

The spelling of 281209 in words is "two hundred eighty-one thousand, two hundred nine".