646678 has 4 divisors (see below), whose sum is σ = 970020.
Its totient is φ = 323338.
The previous prime is 646669. The next prime is 646687. The reversal of 646678 is 876646.
It is a semiprime because it is the product of two primes.
It is an interprime number because it is at equal distance from previous prime (646669) and next prime (646687).
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 as a sum of consecutive naturals, namely, 161668 + ... + 161671.
It is an arithmetic number, because the mean of its divisors is an integer number (242505).
2646678 is an apocalyptic number.
646678 is a deficient number, since it is larger than the sum of its proper divisors (323342).
646678 is a wasteful number, since it uses less digits than its factorization.
646678 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 323341.
The product of its digits is 48384, while the sum is 37.
The square root of 646678 is about 804.1629188168.
The cubic root of 646678 is about 86.4760868108.
The spelling of 646678 in words is "six hundred forty-six thousand, six hundred seventy-eight".