491997 has 16 divisors (see below), whose sum is σ = 758592. Its totient is φ = 280320.

The previous prime is 491983. The next prime is 492007. The reversal of 491997 is 799194.

It is not a de Polignac number, because 491997 - 2¹⁴ = 475613 is a prime.

It is a super-2 number, since 2×491997² = 484122096018, which contains 22 as substring.

491997 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 123 + ... + 999.

It is an arithmetic number, because the mean of its divisors is an integer number (47412).

2⁴⁹¹⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

491997 is a deficient number, since it is larger than the sum of its proper divisors (266595).

491997 is a wasteful number, since it uses less digits than its factorization.

491997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 908.

The product of its digits is 20412, while the sum is 39.

The square root of 491997 is about 701.4249781694. The cubic root of 491997 is about 78.9443072731.

The spelling of 491997 in words is "four hundred ninety-one thousand, nine hundred ninety-seven".