905609 has 4 divisors (see below), whose sum is σ = 910404. Its totient is φ = 900816.

The previous prime is 905599. The next prime is 905617. The reversal of 905609 is 906509.

905609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 906509 = 19 ⋅47711.

It can be written as a sum of positive squares in 2 ways, for example, as 511225 + 394384 = 715^2 + 628^2 .

It is a cyclic number.

It is not a de Polignac number, because 905609 - 2¹² = 901513 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (905629) 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, 2102 + ... + 2495.

It is an arithmetic number, because the mean of its divisors is an integer number (227601).

2⁹⁰⁵⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

905609 is a deficient number, since it is larger than the sum of its proper divisors (4795).

905609 is a wasteful number, since it uses less digits than its factorization.

905609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4794.

The product of its (nonzero) digits is 2430, while the sum is 29.

The square root of 905609 is about 951.6349089856. The cubic root of 905609 is about 96.7490947085.

Subtracting 905609 from its reverse (906509), we obtain a square (900 = 30²).

The spelling of 905609 in words is "nine hundred five thousand, six hundred nine".