1280389 has 16 divisors (see below), whose sum is σ = 1524096. Its totient is φ = 1062400.

The previous prime is 1280371. The next prime is 1280399. The reversal of 1280389 is 9830821.

It is a cyclic number.

It is not a de Polignac number, because 1280389 - 2⁹ = 1279877 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1280389.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1280309) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7584 + ... + 7750.

It is an arithmetic number, because the mean of its divisors is an integer number (95256).

2^1280389 is an apocalyptic number.

It is an amenable number.

1280389 is a deficient number, since it is larger than the sum of its proper divisors (243707).

1280389 is a wasteful number, since it uses less digits than its factorization.

1280389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 1280389 is about 1131.5427521751. The cubic root of 1280389 is about 108.5877025961.

The spelling of 1280389 in words is "one million, two hundred eighty thousand, three hundred eighty-nine".