646579 has 4 divisors (see below), whose sum is σ = 660384. Its totient is φ = 632776.

The previous prime is 646577. The next prime is 646609. The reversal of 646579 is 975646.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 646579 - 2¹ = 646577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646571) 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 3 ways as a sum of consecutive naturals, for example, 6832 + ... + 6925.

It is an arithmetic number, because the mean of its divisors is an integer number (165096).

2⁶⁴⁶⁵⁷⁹ is an apocalyptic number.

646579 is a deficient number, since it is larger than the sum of its proper divisors (13805).

646579 is a wasteful number, since it uses less digits than its factorization.

646579 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13804.

The product of its digits is 45360, while the sum is 37.

The square root of 646579 is about 804.1013617698. The cubic root of 646579 is about 86.4716737080.

It can be divided in two parts, 646 and 579, that added together give a triangular number (1225 = T₄₉).

The spelling of 646579 in words is "six hundred forty-six thousand, five hundred seventy-nine".