491698591 has 2 divisors, whose sum is σ = 491698592. Its totient is φ = 491698590.

The previous prime is 491698579. The next prime is 491698621. The reversal of 491698591 is 195896194.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 491698591 - 2⁹ = 491698079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (491698541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245849295 + 245849296.

It is an arithmetic number, because the mean of its divisors is an integer number (245849296).

Almost surely, 2^491698591 is an apocalyptic number.

491698591 is a deficient number, since it is larger than the sum of its proper divisors (1).

491698591 is an equidigital number, since it uses as much as digits as its factorization.

491698591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 699840, while the sum is 52.

The square root of 491698591 is about 22174.2776883487. The cubic root of 491698591 is about 789.2834345208.

The spelling of 491698591 in words is "four hundred ninety-one million, six hundred ninety-eight thousand, five hundred ninety-one".