491609 has 4 divisors (see below), whose sum is σ = 497616. Its totient is φ = 485604.

The previous prime is 491593. The next prime is 491611. The reversal of 491609 is 906194.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 491609 - 2⁴ = 491593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491639) 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, 2879 + ... + 3044.

It is an arithmetic number, because the mean of its divisors is an integer number (124404).

2⁴⁹¹⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

491609 is a deficient number, since it is larger than the sum of its proper divisors (6007).

491609 is an equidigital number, since it uses as much as digits as its factorization.

491609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6006.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 491609 is about 701.1483437904. The cubic root of 491609 is about 78.9235493913.

The spelling of 491609 in words is "four hundred ninety-one thousand, six hundred nine".