491975846819 has 4 divisors (see below), whose sum is σ = 492794442840. Its totient is φ = 491157250800.

The previous prime is 491975846737. The next prime is 491975846821. The reversal of 491975846819 is 918648579194.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491975846819 is a prime.

It is a super-3 number, since 3×491975846819³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491975846839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 409297109 + ... + 409298310.

It is an arithmetic number, because the mean of its divisors is an integer number (123198610710).

Almost surely, 2^491975846819 is an apocalyptic number.

491975846819 is a deficient number, since it is larger than the sum of its proper divisors (818596021).

491975846819 is an equidigital number, since it uses as much as digits as its factorization.

491975846819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 818596020.

The product of its digits is 156764160, while the sum is 71.

The spelling of 491975846819 in words is "four hundred ninety-one billion, nine hundred seventy-five million, eight hundred forty-six thousand, eight hundred nineteen".