280864 has 24 divisors (see below), whose sum is σ = 565488. Its totient is φ = 137280.

The previous prime is 280859. The next prime is 280871. The reversal of 280864 is 468082.

280864 = T₅₆ + T₅₇ + ... + T₁₂₂.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a plaindrome in base 13.

It is an unprimeable number.

280864 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2079 + ... + 2209.

It is an arithmetic number, because the mean of its divisors is an integer number (23562).

2²⁸⁰⁸⁶⁴ is an apocalyptic number.

It is an amenable number.

280864 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

280864 is a wasteful number, since it uses less digits than its factorization.

280864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208 (or 200 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 280864 is about 529.9660366476. The cubic root of 280864 is about 65.4885476160.

The spelling of 280864 in words is "two hundred eighty thousand, eight hundred sixty-four".