491217123 has 4 divisors (see below), whose sum is σ = 654956168. Its totient is φ = 327478080.

The previous prime is 491217113. The next prime is 491217149. The reversal of 491217123 is 321712194.

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

It is not a de Polignac number, because 491217123 - 2⁶ = 491217059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491217113) 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, 81869518 + ... + 81869523.

It is an arithmetic number, because the mean of its divisors is an integer number (163739042).

Almost surely, 2^491217123 is an apocalyptic number.

491217123 is a deficient number, since it is larger than the sum of its proper divisors (163739045).

491217123 is a wasteful number, since it uses less digits than its factorization.

491217123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163739044.

The product of its digits is 3024, while the sum is 30.

The square root of 491217123 is about 22163.4185765644. The cubic root of 491217123 is about 789.0257300198.

It can be divided in two parts, 4912171 and 23, that added together give a palindrome (4912194).

The spelling of 491217123 in words is "four hundred ninety-one million, two hundred seventeen thousand, one hundred twenty-three".