1985806 has 4 divisors (see below), whose sum is σ = 2978712. Its totient is φ = 992902.

The previous prime is 1985803. The next prime is 1985849. The reversal of 1985806 is 6085891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6085891 = 7 ⋅869413.

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 as a sum of consecutive naturals, namely, 496450 + ... + 496453.

It is an arithmetic number, because the mean of its divisors is an integer number (744678).

2^1985806 is an apocalyptic number.

1985806 is a deficient number, since it is larger than the sum of its proper divisors (992906).

1985806 is an equidigital number, since it uses as much as digits as its factorization.

1985806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 992905.

The product of its (nonzero) digits is 17280, while the sum is 37.

The square root of 1985806 is about 1409.1862900270. The cubic root of 1985806 is about 125.6933417736.

The spelling of 1985806 in words is "one million, nine hundred eighty-five thousand, eight hundred six".