491815 has 16 divisors (see below), whose sum is σ = 645120. Its totient is φ = 358560.

The previous prime is 491797. The next prime is 491819. The reversal of 491815 is 518194.

It is a happy number.

It is not a de Polignac number, because 491815 - 2⁵ = 491783 is a prime.

491815 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491819) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2862 + ... + 3028.

It is an arithmetic number, because the mean of its divisors is an integer number (40320).

2⁴⁹¹⁸¹⁵ is an apocalyptic number.

491815 is a deficient number, since it is larger than the sum of its proper divisors (153305).

491815 is a wasteful number, since it uses less digits than its factorization.

491815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222.

The product of its digits is 1440, while the sum is 28.

The square root of 491815 is about 701.2952302704. The cubic root of 491815 is about 78.9345716880.

It can be divided in two parts, 4 and 91815, that added together give a palindrome (91819).

The spelling of 491815 in words is "four hundred ninety-one thousand, eight hundred fifteen".