491808193 has 4 divisors (see below), whose sum is σ = 491856640. Its totient is φ = 491759748.

The previous prime is 491808173. The next prime is 491808199. The reversal of 491808193 is 391808194.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, 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-491808193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491808199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2505 + ... + 31462.

It is an arithmetic number, because the mean of its divisors is an integer number (122964160).

Almost surely, 2^491808193 is an apocalyptic number.

It is an amenable number.

491808193 is a deficient number, since it is larger than the sum of its proper divisors (48447).

491808193 is a wasteful number, since it uses less digits than its factorization.

491808193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48446.

The product of its (nonzero) digits is 62208, while the sum is 43.

The square root of 491808193 is about 22176.7489276494. The cubic root of 491808193 is about 789.3420751988.

Subtracting from 491808193 its reverse (391808194), we obtain a palindrome (99999999).

The spelling of 491808193 in words is "four hundred ninety-one million, eight hundred eight thousand, one hundred ninety-three".