1285805 has 4 divisors (see below), whose sum is σ = 1542972. Its totient is φ = 1028640.

The previous prime is 1285799. The next prime is 1285811. The reversal of 1285805 is 5085821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5085821 = 13 ⋅391217.

It is an interprime number because it is at equal distance from previous prime (1285799) and next prime (1285811).

It can be written as a sum of positive squares in 2 ways, for example, as 413449 + 872356 = 643^2 + 934^2 .

It is not a de Polignac number, because 1285805 - 2⁴ = 1285789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128576 + ... + 128585.

It is an arithmetic number, because the mean of its divisors is an integer number (385743).

2^1285805 is an apocalyptic number.

It is an amenable number.

1285805 is a deficient number, since it is larger than the sum of its proper divisors (257167).

1285805 is an equidigital number, since it uses as much as digits as its factorization.

1285805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257166.

The product of its (nonzero) digits is 3200, while the sum is 29.

The square root of 1285805 is about 1133.9334195622. The cubic root of 1285805 is about 108.7405945977.

The spelling of 1285805 in words is "one million, two hundred eighty-five thousand, eight hundred five".