280440 has 96 divisors (see below), whose sum is σ = 982800. Its totient is φ = 69120.

The previous prime is 280411. The next prime is 280451. The reversal of 280440 is 44082.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

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 280440.

It is an unprimeable number.

280440 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6820 + ... + 6860.

2²⁸⁰⁴⁴⁰ is an apocalyptic number.

280440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 280440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (491400).

280440 is an abundant number, since it is smaller than the sum of its proper divisors (702360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

280440 is a wasteful number, since it uses less digits than its factorization.

280440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 280440 is about 529.5658599268. The cubic root of 280440 is about 65.4555765831.

The spelling of 280440 in words is "two hundred eighty thousand, four hundred forty".