1685945 has 4 divisors (see below), whose sum is σ = 2023140. Its totient is φ = 1348752.

The previous prime is 1685933. The next prime is 1685951. The reversal of 1685945 is 5495861.

1685945 is an esthetic number in base 4, because in such base its adjacent digits differ by 1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5495861 = 7 ⋅785123.

It can be written as a sum of positive squares in 2 ways, for example, as 284089 + 1401856 = 533^2 + 1184^2 .

It is a cyclic number.

It is not a de Polignac number, because 1685945 - 2⁶ = 1685881 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1685899 and 1685908.

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, 168590 + ... + 168599.

It is an arithmetic number, because the mean of its divisors is an integer number (505785).

2^1685945 is an apocalyptic number.

It is an amenable number.

1685945 is a deficient number, since it is larger than the sum of its proper divisors (337195).

1685945 is an equidigital number, since it uses as much as digits as its factorization.

1685945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337194.

The product of its digits is 43200, while the sum is 38.

The square root of 1685945 is about 1298.4394479528. The cubic root of 1685945 is about 119.0184986425.

The spelling of 1685945 in words is "one million, six hundred eighty-five thousand, nine hundred forty-five".