491221913 has 24 divisors (see below), whose sum is σ = 621214272. Its totient is φ = 384973344.

The previous prime is 491221897. The next prime is 491221931. The reversal of 491221913 is 319122194.

It is not a de Polignac number, because 491221913 - 2⁴ = 491221897 is a prime.

It is a super-2 number, since 2×491221913² = 482597935622759138, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 491221913.

It is not an unprimeable number, because it can be changed into a prime (491221993) 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 23 ways as a sum of consecutive naturals, for example, 64556 + ... + 71762.

It is an arithmetic number, because the mean of its divisors is an integer number (25883928).

Almost surely, 2^491221913 is an apocalyptic number.

It is an amenable number.

491221913 is a deficient number, since it is larger than the sum of its proper divisors (129992359).

491221913 is a wasteful number, since it uses less digits than its factorization.

491221913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7341 (or 7334 counting only the distinct ones).

The product of its digits is 3888, while the sum is 32.

The square root of 491221913 is about 22163.5266372480. The cubic root of 491221913 is about 789.0282946840.

It can be divided in two parts, 49122191 and 3, that added together give a palindrome (49122194).

The spelling of 491221913 in words is "four hundred ninety-one million, two hundred twenty-one thousand, nine hundred thirteen".