281309 has 6 divisors (see below), whose sum is σ = 327294. Its totient is φ = 241080.

The previous prime is 281297. The next prime is 281317. The reversal of 281309 is 903182.

It can be written as a sum of positive squares in only one way, i.e., 240100 + 41209 = 490^2 + 203^2 .

It is not a de Polignac number, because 281309 - 2⁸ = 281053 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 281309.

It is not an unprimeable number, because it can be changed into a prime (281339) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2822 + ... + 2919.

It is an arithmetic number, because the mean of its divisors is an integer number (54549).

2²⁸¹³⁰⁹ is an apocalyptic number.

It is an amenable number.

281309 is a deficient number, since it is larger than the sum of its proper divisors (45985).

281309 is an equidigital number, since it uses as much as digits as its factorization.

281309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5755 (or 5748 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 281309 is about 530.3857087064. The cubic root of 281309 is about 65.5231159791.

The spelling of 281309 in words is "two hundred eighty-one thousand, three hundred nine".