491668 has 12 divisors (see below), whose sum is σ = 869652. Its totient is φ = 243200.

The previous prime is 491653. The next prime is 491669. The reversal of 491668 is 866194.

It can be written as a sum of positive squares in 2 ways, for example, as 345744 + 145924 = 588^2 + 382^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491669) by changing a digit.

491668 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 205 + ... + 1012.

It is an arithmetic number, because the mean of its divisors is an integer number (72471).

2⁴⁹¹⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

491668 is a deficient number, since it is larger than the sum of its proper divisors (377984).

491668 is a wasteful number, since it uses less digits than its factorization.

491668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1322 (or 1320 counting only the distinct ones).

The product of its digits is 10368, while the sum is 34.

The square root of 491668 is about 701.1904163635. The cubic root of 491668 is about 78.9267065773.

The spelling of 491668 in words is "four hundred ninety-one thousand, six hundred sixty-eight".