1985805 has 12 divisors (see below), whose sum is σ = 3442140. Its totient is φ = 1059072.

The previous prime is 1985803. The next prime is 1985849. The reversal of 1985805 is 5085891.

1985805 is nontrivially palindromic in base 14.

It can be written as a sum of positive squares in 2 ways, for example, as 227529 + 1758276 = 477^2 + 1326^2 .

It is not a de Polignac number, because 1985805 - 2¹ = 1985803 is a prime.

1985805 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1985805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1985803) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 22020 + ... + 22109.

It is an arithmetic number, because the mean of its divisors is an integer number (286845).

2^1985805 is an apocalyptic number.

1985805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1985805 is a deficient number, since it is larger than the sum of its proper divisors (1456335).

1985805 is a wasteful number, since it uses less digits than its factorization.

1985805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44140 (or 44137 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 36.

The square root of 1985805 is about 1409.1859352122. The cubic root of 1985805 is about 125.6933206750.

The spelling of 1985805 in words is "one million, nine hundred eighty-five thousand, eight hundred five".