1280845 has 4 divisors (see below), whose sum is σ = 1537020. Its totient is φ = 1024672.

The previous prime is 1280837. The next prime is 1280857. The reversal of 1280845 is 5480821.

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

It can be written as a sum of positive squares in 2 ways, for example, as 203401 + 1077444 = 451^2 + 1038^2 .

It is a cyclic number.

It is not a de Polignac number, because 1280845 - 2³ = 1280837 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128080 + ... + 128089.

It is an arithmetic number, because the mean of its divisors is an integer number (384255).

2^1280845 is an apocalyptic number.

It is an amenable number.

1280845 is a deficient number, since it is larger than the sum of its proper divisors (256175).

1280845 is an equidigital number, since it uses as much as digits as its factorization.

1280845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256174.

The product of its (nonzero) digits is 2560, while the sum is 28.

The square root of 1280845 is about 1131.7442290553. The cubic root of 1280845 is about 108.6005919382.

It can be divided in two parts, 1280 and 845, that multiplied together give a square (1081600 = 1040²).

The spelling of 1280845 in words is "one million, two hundred eighty thousand, eight hundred forty-five".