635609 has 6 divisors (see below), whose sum is σ = 688446. Its totient is φ = 586560.

The previous prime is 635603. The next prime is 635617. The reversal of 635609 is 906536.

It can be written as a sum of positive squares in 3 ways, for example, as 400 + 635209 = 20^2 + 797^2 .

It is not a de Polignac number, because 635609 - 2⁸ = 635353 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (635603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1712 + ... + 2049.

It is an arithmetic number, because the mean of its divisors is an integer number (114741).

2⁶³⁵⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

635609 is a deficient number, since it is larger than the sum of its proper divisors (52837).

635609 is a wasteful number, since it uses less digits than its factorization.

635609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3787 (or 3774 counting only the distinct ones).

The product of its (nonzero) digits is 4860, while the sum is 29.

The square root of 635609 is about 797.2509015360. The cubic root of 635609 is about 85.9798492539.

The spelling of 635609 in words is "six hundred thirty-five thousand, six hundred nine".