491321915 has 16 divisors (see below), whose sum is σ = 697049280. Its totient is φ = 325288320.

The previous prime is 491321911. The next prime is 491321939. The reversal of 491321915 is 519123194.

It is a happy number.

It is not a de Polignac number, because 491321915 - 2² = 491321911 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is not an unprimeable number, because it can be changed into a prime (491321911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 241016 + ... + 243045.

It is an arithmetic number, because the mean of its divisors is an integer number (43565580).

Almost surely, 2^491321915 is an apocalyptic number.

491321915 is a deficient number, since it is larger than the sum of its proper divisors (205727365).

491321915 is a wasteful number, since it uses less digits than its factorization.

491321915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484102.

The product of its digits is 9720, while the sum is 35.

The square root of 491321915 is about 22165.7825262272. The cubic root of 491321915 is about 789.0818339987.

The spelling of 491321915 in words is "four hundred ninety-one million, three hundred twenty-one thousand, nine hundred fifteen".