491431909 has 2 divisors, whose sum is σ = 491431910. Its totient is φ = 491431908.

The previous prime is 491431879. The next prime is 491431943. The reversal of 491431909 is 909134194.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 332041284 + 159390625 = 18222^2 + 12625^2 .

It is a cyclic number.

It is not a de Polignac number, because 491431909 - 2⁵ = 491431877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (491431009) 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, 245715954 + 245715955.

It is an arithmetic number, because the mean of its divisors is an integer number (245715955).

Almost surely, 2^491431909 is an apocalyptic number.

It is an amenable number.

491431909 is a deficient number, since it is larger than the sum of its proper divisors (1).

491431909 is an equidigital number, since it uses as much as digits as its factorization.

491431909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 40.

The square root of 491431909 is about 22168.2635540089. The cubic root of 491431909 is about 789.1407144655.

The spelling of 491431909 in words is "four hundred ninety-one million, four hundred thirty-one thousand, nine hundred nine".