491865 has 24 divisors (see below), whose sum is σ = 868224. Its totient is φ = 237600.

The previous prime is 491857. The next prime is 491867. The reversal of 491865 is 568194.

491865 = T₄₆ + T₄₇ + ... + T₁₄₄.

It is not a de Polignac number, because 491865 - 2³ = 491857 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (491867) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1680 + ... + 1950.

It is an arithmetic number, because the mean of its divisors is an integer number (36176).

2⁴⁹¹⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

491865 is a deficient number, since it is larger than the sum of its proper divisors (376359).

491865 is a wasteful number, since it uses less digits than its factorization.

491865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 301 (or 290 counting only the distinct ones).

The product of its digits is 8640, while the sum is 33.

The square root of 491865 is about 701.3308776890. The cubic root of 491865 is about 78.9372465386.

The spelling of 491865 in words is "four hundred ninety-one thousand, eight hundred sixty-five".