1678345 has 4 divisors (see below), whose sum is σ = 2014020. Its totient is φ = 1342672.

The previous prime is 1678337. The next prime is 1678349. The reversal of 1678345 is 5438761.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5438761 = 1901 ⋅2861.

It can be written as a sum of positive squares in 2 ways, for example, as 741321 + 937024 = 861^2 + 968^2 .

It is a cyclic number.

It is not a de Polignac number, because 1678345 - 2³ = 1678337 is a prime.

It is an alternating number because its digits alternate between odd and even.

1678345 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1678345.

It is not an unprimeable number, because it can be changed into a prime (1678349) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 167830 + ... + 167839.

It is an arithmetic number, because the mean of its divisors is an integer number (503505).

2^1678345 is an apocalyptic number.

It is an amenable number.

1678345 is a deficient number, since it is larger than the sum of its proper divisors (335675).

1678345 is an equidigital number, since it uses as much as digits as its factorization.

1678345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 335674.

The product of its digits is 20160, while the sum is 34.

The square root of 1678345 is about 1295.5095522612. The cubic root of 1678345 is about 118.8393897582.

It can be divided in two parts, 167 and 8345, that multiplied together give a triangular number (1393615 = T₁₆₆₉).

The spelling of 1678345 in words is "one million, six hundred seventy-eight thousand, three hundred forty-five".