509645 has 4 divisors (see below), whose sum is σ = 611580. Its totient is φ = 407712.

The previous prime is 509633. The next prime is 509647. The reversal of 509645 is 546905.

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

It can be written as a sum of positive squares in 2 ways, for example, as 334084 + 175561 = 578^2 + 419^2 .

It is a cyclic number.

It is not a de Polignac number, because 509645 - 2⁶ = 509581 is a prime.

It is a super-3 number, since 3×509645³ = 397122558820533375, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (509647) 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, 50960 + ... + 50969.

It is an arithmetic number, because the mean of its divisors is an integer number (152895).

2⁵⁰⁹⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

509645 is a deficient number, since it is larger than the sum of its proper divisors (101935).

509645 is a wasteful number, since it uses less digits than its factorization.

509645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101934.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 509645 is about 713.8942498718. The cubic root of 509645 is about 79.8771552110.

The spelling of 509645 in words is "five hundred nine thousand, six hundred forty-five".