491917 has 4 divisors (see below), whose sum is σ = 496540. Its totient is φ = 487296.

The previous prime is 491899. The next prime is 491923. The reversal of 491917 is 719194.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 114921 + 376996 = 339^2 + 614^2 .

It is a cyclic number.

It is not a de Polignac number, because 491917 - 2⁷ = 491789 is a prime.

It is a Duffinian number.

491917 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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2148 + ... + 2365.

It is an arithmetic number, because the mean of its divisors is an integer number (124135).

2⁴⁹¹⁹¹⁷ is an apocalyptic number.

It is an amenable number.

491917 is a deficient number, since it is larger than the sum of its proper divisors (4623).

491917 is a wasteful number, since it uses less digits than its factorization.

491917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4622.

The product of its digits is 2268, while the sum is 31.

The square root of 491917 is about 701.3679490824. The cubic root of 491917 is about 78.9400281908.

The spelling of 491917 in words is "four hundred ninety-one thousand, nine hundred seventeen".