1678 has 4 divisors (see below), whose sum is σ = 2520.
Its totient is φ = 838.
The previous prime is 1669. The next prime is 1693. The reversal of 1678 is 8761.
It is a semiprime because it is the product of two primes.
It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.
It is an alternating number because its digits alternate between odd and even.
It is a plaindrome in base 10 and base 16.
It is a congruent number.
It is an unprimeable number.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 418 + ... + 421.
It is an arithmetic number, because the mean of its divisors is an integer number (630).
1678 is a deficient number, since it is larger than the sum of its proper divisors (842).
1678 is an equidigital number, since it uses as much as digits as its factorization.
1678 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 841.
The product of its digits is 336, while the sum is 22.
The square root of 1678 is about 40.9633982965.
The cubic root of 1678 is about 11.8831246339.
The spelling of 1678 in words is "one thousand, six hundred seventy-eight".