280091 has 4 divisors (see below), whose sum is σ = 320112. Its totient is φ = 240072.

The previous prime is 280069. The next prime is 280097. The reversal of 280091 is 190082.

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

It is a de Polignac number, because none of the positive numbers 2^k-280091 is a prime.

It is a Duffinian number.

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 280091.

It is not an unprimeable number, because it can be changed into a prime (280097) 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, 20000 + ... + 20013.

It is an arithmetic number, because the mean of its divisors is an integer number (80028).

2²⁸⁰⁰⁹¹ is an apocalyptic number.

280091 is a deficient number, since it is larger than the sum of its proper divisors (40021).

280091 is an equidigital number, since it uses as much as digits as its factorization.

280091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40020.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 280091 is about 529.2362421452. The cubic root of 280091 is about 65.4284127465.

Subtracting from 280091 its reverse (190082), we obtain a palindrome (90009).

The spelling of 280091 in words is "two hundred eighty thousand, ninety-one".