646606 has 8 divisors (see below), whose sum is σ = 974304. Its totient is φ = 321840.

The previous prime is 646577. The next prime is 646609. The reversal of 646606 is 606646.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646609) by changing a digit.

646606 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55 + ... + 1138.

It is an arithmetic number, because the mean of its divisors is an integer number (121788).

2⁶⁴⁶⁶⁰⁶ is an apocalyptic number.

646606 is a deficient number, since it is larger than the sum of its proper divisors (327698).

646606 is a wasteful number, since it uses less digits than its factorization.

646606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1466.

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 646606 is about 804.1181505227. The cubic root of 646606 is about 86.4728773262.

It can be divided in two parts, 64 and 6606, that added together give a triangular number (6670 = T₁₁₅).

The spelling of 646606 in words is "six hundred forty-six thousand, six hundred six".