491866589 has 2 divisors, whose sum is σ = 491866590. Its totient is φ = 491866588.

The previous prime is 491866537. The next prime is 491866619. The reversal of 491866589 is 985668194.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 274068025 + 217798564 = 16555^2 + 14758^2 .

It is a cyclic number.

It is not a de Polignac number, because 491866589 - 2¹² = 491862493 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (491866519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245933294 + 245933295.

It is an arithmetic number, because the mean of its divisors is an integer number (245933295).

Almost surely, 2^491866589 is an apocalyptic number.

It is an amenable number.

491866589 is a deficient number, since it is larger than the sum of its proper divisors (1).

491866589 is an equidigital number, since it uses as much as digits as its factorization.

491866589 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3732480, while the sum is 56.

The square root of 491866589 is about 22178.0654927340. The cubic root of 491866589 is about 789.3733154236.

The spelling of 491866589 in words is "four hundred ninety-one million, eight hundred sixty-six thousand, five hundred eighty-nine".