646005 has 8 divisors (see below), whose sum is σ = 1033632. Its totient is φ = 344528.

The previous prime is 646003. The next prime is 646013. The reversal of 646005 is 500646.

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

It is a cyclic number.

It is not a de Polignac number, because 646005 - 2¹ = 646003 is a prime.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646003) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 21519 + ... + 21548.

It is an arithmetic number, because the mean of its divisors is an integer number (129204).

2⁶⁴⁶⁰⁰⁵ is an apocalyptic number.

It is an amenable number.

646005 is a deficient number, since it is larger than the sum of its proper divisors (387627).

646005 is a wasteful number, since it uses less digits than its factorization.

646005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43075.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 646005 is about 803.7443623441. The cubic root of 646005 is about 86.4460777454.

The spelling of 646005 in words is "six hundred forty-six thousand, five".