491760809 has 2 divisors, whose sum is σ = 491760810. Its totient is φ = 491760808.

The previous prime is 491760799. The next prime is 491760817. The reversal of 491760809 is 908067194.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 485232784 + 6528025 = 22028^2 + 2555^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491760809 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 491760809.

It is not a weakly prime, because it can be changed into another prime (491766809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245880404 + 245880405.

It is an arithmetic number, because the mean of its divisors is an integer number (245880405).

Almost surely, 2^491760809 is an apocalyptic number.

It is an amenable number.

491760809 is a deficient number, since it is larger than the sum of its proper divisors (1).

491760809 is an equidigital number, since it uses as much as digits as its factorization.

491760809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 491760809 is about 22175.6805758020. The cubic root of 491760809 is about 789.3167242681.

The spelling of 491760809 in words is "four hundred ninety-one million, seven hundred sixty thousand, eight hundred nine".