491791 has 4 divisors (see below), whose sum is σ = 503272. Its totient is φ = 480312.

The previous prime is 491789. The next prime is 491797. The reversal of 491791 is 197194.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 197194 = 2 ⋅98597.

It is a cyclic number.

It is not a de Polignac number, because 491791 - 2¹ = 491789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491797) 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, 5676 + ... + 5761.

It is an arithmetic number, because the mean of its divisors is an integer number (125818).

2⁴⁹¹⁷⁹¹ is an apocalyptic number.

491791 is a deficient number, since it is larger than the sum of its proper divisors (11481).

491791 is a wasteful number, since it uses less digits than its factorization.

491791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11480.

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

The square root of 491791 is about 701.2781188658. The cubic root of 491791 is about 78.9332876954.

The spelling of 491791 in words is "four hundred ninety-one thousand, seven hundred ninety-one".