280388 has 12 divisors (see below), whose sum is σ = 494592. Its totient is φ = 139080.

The previous prime is 280373. The next prime is 280409. The reversal of 280388 is 883082.

280388 is nontrivially palindromic in base 16.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 280388.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 581 + ... + 947.

It is an arithmetic number, because the mean of its divisors is an integer number (41216).

2²⁸⁰³⁸⁸ is an apocalyptic number.

It is an amenable number.

280388 is a deficient number, since it is larger than the sum of its proper divisors (214204).

280388 is a wasteful number, since it uses less digits than its factorization.

280388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 562 (or 560 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 280388 is about 529.5167608301. The cubic root of 280388 is about 65.4515306786.

The spelling of 280388 in words is "two hundred eighty thousand, three hundred eighty-eight".