646563 has 4 divisors (see below), whose sum is σ = 862088. Its totient is φ = 431040.

The previous prime is 646549. The next prime is 646571. The reversal of 646563 is 365646.

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

It is not a de Polignac number, because 646563 - 2⁸ = 646307 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 646563.

It is not an unprimeable number, because it can be changed into a prime (646523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107758 + ... + 107763.

It is an arithmetic number, because the mean of its divisors is an integer number (215522).

2⁶⁴⁶⁵⁶³ is an apocalyptic number.

646563 is a deficient number, since it is larger than the sum of its proper divisors (215525).

646563 is a wasteful number, since it uses less digits than its factorization.

646563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215524.

The product of its digits is 12960, while the sum is 30.

The square root of 646563 is about 804.0914127138. The cubic root of 646563 is about 86.4709604370.

It can be divided in two parts, 6 and 46563, that multiplied together give a triangular number (279378 = T₇₄₇).

The spelling of 646563 in words is "six hundred forty-six thousand, five hundred sixty-three".