280813 has 4 divisors (see below), whose sum is σ = 302428. Its totient is φ = 259200.

The previous prime is 280811. The next prime is 280817. The reversal of 280813 is 318082.

280813 is nontrivially palindromic in base 12.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 149769 + 131044 = 387^2 + 362^2 .

It is a cyclic number.

It is not a de Polignac number, because 280813 - 2¹ = 280811 is a prime.

It is a Duffinian number.

It is a zygodrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (280811) 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, 10788 + ... + 10813.

It is an arithmetic number, because the mean of its divisors is an integer number (75607).

2²⁸⁰⁸¹³ is an apocalyptic number.

It is an amenable number.

280813 is a deficient number, since it is larger than the sum of its proper divisors (21615).

280813 is a wasteful number, since it uses less digits than its factorization.

280813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21614.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 280813 is about 529.9179181722. The cubic root of 280813 is about 65.4845835170.

Adding to 280813 its reverse (318082), we get a palindrome (598895).

The spelling of 280813 in words is "two hundred eighty thousand, eight hundred thirteen".