646506 has 36 divisors (see below), whose sum is σ = 1631682. Its totient is φ = 184464.

The previous prime is 646453. The next prime is 646519. The reversal of 646506 is 605646.

646506 is a `hidden beast` number, since 6 + 4 + 650 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 370881 + 275625 = 609^2 + 525^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 646506.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 646506.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 516 + ... + 1248.

2⁶⁴⁶⁵⁰⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646506, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (815841).

646506 is an abundant number, since it is smaller than the sum of its proper divisors (985176).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

646506 is a wasteful number, since it uses less digits than its factorization.

646506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 755 (or 745 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 646506 is about 804.0559682012. The cubic root of 646506 is about 86.4684193133.

The spelling of 646506 in words is "six hundred forty-six thousand, five hundred six".