280765 has 8 divisors (see below), whose sum is σ = 339768. Its totient is φ = 222720.

The previous prime is 280759. The next prime is 280769. The reversal of 280765 is 567082.

It can be written as a sum of positive squares in 4 ways, for example, as 23716 + 257049 = 154^2 + 507^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 280765 - 2⁹ = 280253 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (280769) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1045 + ... + 1285.

It is an arithmetic number, because the mean of its divisors is an integer number (42471).

2²⁸⁰⁷⁶⁵ is an apocalyptic number.

It is an amenable number.

280765 is a deficient number, since it is larger than the sum of its proper divisors (59003).

280765 is a wasteful number, since it uses less digits than its factorization.

280765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 479.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 280765 is about 529.8726262037. The cubic root of 280765 is about 65.4808521619.

The spelling of 280765 in words is "two hundred eighty thousand, seven hundred sixty-five".