491687 has 4 divisors (see below), whose sum is σ = 561936. Its totient is φ = 421440.

The previous prime is 491677. The next prime is 491707. The reversal of 491687 is 786194.

491687 = T₂₅₈ + T₂₅₉ + ... + T₂₇₁.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 786194 = 2 ⋅393097.

It is a cyclic number.

It is not a de Polignac number, because 491687 - 2¹⁰ = 490663 is a prime.

It is a super-2 number, since 2×491687² = 483512211938, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 491687.

It is not an unprimeable number, because it can be changed into a prime (491627) 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, 35114 + ... + 35127.

It is an arithmetic number, because the mean of its divisors is an integer number (140484).

2⁴⁹¹⁶⁸⁷ is an apocalyptic number.

491687 is a deficient number, since it is larger than the sum of its proper divisors (70249).

491687 is an equidigital number, since it uses as much as digits as its factorization.

491687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70248.

The product of its digits is 12096, while the sum is 35.

The square root of 491687 is about 701.2039646209. The cubic root of 491687 is about 78.9277232445.

The spelling of 491687 in words is "four hundred ninety-one thousand, six hundred eighty-seven".