491500609 has 4 divisors (see below), whose sum is σ = 492893316. Its totient is φ = 490107904.

The previous prime is 491500601. The next prime is 491500673. The reversal of 491500609 is 906005194.

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 354493584 + 137007025 = 18828^2 + 11705^2 .

It is a cyclic number.

It is not a de Polignac number, because 491500609 - 2³ = 491500601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491500601) 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, 695824 + ... + 696529.

It is an arithmetic number, because the mean of its divisors is an integer number (123223329).

Almost surely, 2^491500609 is an apocalyptic number.

It is an amenable number.

491500609 is a deficient number, since it is larger than the sum of its proper divisors (1392707).

491500609 is a wasteful number, since it uses less digits than its factorization.

491500609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1392706.

The product of its (nonzero) digits is 9720, while the sum is 34.

The square root of 491500609 is about 22169.8130122922. The cubic root of 491500609 is about 789.1774855420.

The spelling of 491500609 in words is "four hundred ninety-one million, five hundred thousand, six hundred nine".