1285785 has 12 divisors (see below), whose sum is σ = 2228772. Its totient is φ = 685728.

The previous prime is 1285777. The next prime is 1285789. The reversal of 1285785 is 5875821.

It can be written as a sum of positive squares in 2 ways, for example, as 145161 + 1140624 = 381^2 + 1068^2 .

It is not a de Polignac number, because 1285785 - 2³ = 1285777 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1285789) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14242 + ... + 14331.

It is an arithmetic number, because the mean of its divisors is an integer number (185731).

2^1285785 is an apocalyptic number.

1285785 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1285785 is a deficient number, since it is larger than the sum of its proper divisors (942987).

1285785 is a wasteful number, since it uses less digits than its factorization.

1285785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28584 (or 28581 counting only the distinct ones).

The product of its digits is 22400, while the sum is 36.

The square root of 1285785 is about 1133.9246006680. The cubic root of 1285785 is about 108.7400307944.

Adding to 1285785 its sum of digits (36), we get a palindrome (1285821).

The spelling of 1285785 in words is "one million, two hundred eighty-five thousand, seven hundred eighty-five".