491806589 has 4 divisors (see below), whose sum is σ = 492284640. Its totient is φ = 491328540.

The previous prime is 491806541. The next prime is 491806591. The reversal of 491806589 is 985608194.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 985608194 = 2 ⋅492804097.

It is a cyclic number.

It is not a de Polignac number, because 491806589 - 2²⁸ = 223371133 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491806519) 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, 237479 + ... + 239540.

It is an arithmetic number, because the mean of its divisors is an integer number (123071160).

Almost surely, 2^491806589 is an apocalyptic number.

It is an amenable number.

491806589 is a deficient number, since it is larger than the sum of its proper divisors (478051).

491806589 is a wasteful number, since it uses less digits than its factorization.

491806589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478050.

The product of its (nonzero) digits is 622080, while the sum is 50.

The square root of 491806589 is about 22176.7127636176. The cubic root of 491806589 is about 789.3412170688.

The spelling of 491806589 in words is "four hundred ninety-one million, eight hundred six thousand, five hundred eighty-nine".