491831 has 4 divisors (see below), whose sum is σ = 493272. Its totient is φ = 490392.

The previous prime is 491819. The next prime is 491833. The reversal of 491831 is 138194.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491831 is a prime.

It is a super-2 number, since 2×491831² = 483795465122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 491831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491833) 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, 116 + ... + 998.

It is an arithmetic number, because the mean of its divisors is an integer number (123318).

2⁴⁹¹⁸³¹ is an apocalyptic number.

491831 is a deficient number, since it is larger than the sum of its proper divisors (1441).

491831 is an equidigital number, since it uses as much as digits as its factorization.

491831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1440.

The product of its digits is 864, while the sum is 26.

The square root of 491831 is about 701.3066376415. The cubic root of 491831 is about 78.9354276599.

The spelling of 491831 in words is "four hundred ninety-one thousand, eight hundred thirty-one".