491923209 has 8 divisors (see below), whose sum is σ = 660904992. Its totient is φ = 325445120.

The previous prime is 491923199. The next prime is 491923253. The reversal of 491923209 is 902329194.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 491923209 - 2⁴ = 491923193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (491923279) 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 7 ways as a sum of consecutive naturals, for example, 625464 + ... + 626249.

It is an arithmetic number, because the mean of its divisors is an integer number (82613124).

Almost surely, 2^491923209 is an apocalyptic number.

It is an amenable number.

491923209 is a deficient number, since it is larger than the sum of its proper divisors (168981783).

491923209 is a wasteful number, since it uses less digits than its factorization.

491923209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1251847.

The product of its (nonzero) digits is 34992, while the sum is 39.

The square root of 491923209 is about 22179.3419424473. The cubic root of 491923209 is about 789.4036031773.

The spelling of 491923209 in words is "four hundred ninety-one million, nine hundred twenty-three thousand, two hundred nine".