1680565 has 4 divisors (see below), whose sum is σ = 2016684. Its totient is φ = 1344448.

The previous prime is 1680557. The next prime is 1680583. The reversal of 1680565 is 5650861.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 439569 + 1240996 = 663^2 + 1114^2 .

It is a cyclic number.

It is not a de Polignac number, because 1680565 - 2³ = 1680557 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 (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 168052 + ... + 168061.

It is an arithmetic number, because the mean of its divisors is an integer number (504171).

2^1680565 is an apocalyptic number.

It is an amenable number.

1680565 is a deficient number, since it is larger than the sum of its proper divisors (336119).

1680565 is an equidigital number, since it uses as much as digits as its factorization.

1680565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336118.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 1680565 is about 1296.3660748415. The cubic root of 1680565 is about 118.8917642120.

The spelling of 1680565 in words is "one million, six hundred eighty thousand, five hundred sixty-five".