1678945 has 8 divisors (see below), whose sum is σ = 2022120. Its totient is φ = 1338240.

The previous prime is 1678921. The next prime is 1678951. The reversal of 1678945 is 5498761.

It can be written as a sum of positive squares in 4 ways, for example, as 314721 + 1364224 = 561^2 + 1168^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-1678945 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 1678898 and 1678907.

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 7 ways as a sum of consecutive naturals, for example, 1635 + ... + 2455.

It is an arithmetic number, because the mean of its divisors is an integer number (252765).

2^1678945 is an apocalyptic number.

It is an amenable number.

1678945 is a deficient number, since it is larger than the sum of its proper divisors (343175).

1678945 is an equidigital number, since it uses as much as digits as its factorization.

1678945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1235.

The product of its digits is 60480, while the sum is 40.

The square root of 1678945 is about 1295.7411006833. The cubic root of 1678945 is about 118.8535495681.

It can be divided in two parts, 16 and 78945, that added together give a square (78961 = 281²).

The spelling of 1678945 in words is "one million, six hundred seventy-eight thousand, nine hundred forty-five".