491916289 has 12 divisors (see below), whose sum is σ = 521880084. Its totient is φ = 463593312.

The previous prime is 491916223. The next prime is 491916307. The reversal of 491916289 is 982619194.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 421070400 + 70845889 = 20520^2 + 8417^2 .

It is not a de Polignac number, because 491916289 - 2¹⁹ = 491392001 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491916989) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 67659 + ... + 74575.

It is an arithmetic number, because the mean of its divisors is an integer number (43490007).

Almost surely, 2^491916289 is an apocalyptic number.

It is an amenable number.

491916289 is a deficient number, since it is larger than the sum of its proper divisors (29963795).

491916289 is a wasteful number, since it uses less digits than its factorization.

491916289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7152 (or 7133 counting only the distinct ones).

The product of its digits is 279936, while the sum is 49.

The square root of 491916289 is about 22179.1859408771. The cubic root of 491916289 is about 789.3999015842.

The spelling of 491916289 in words is "four hundred ninety-one million, nine hundred sixteen thousand, two hundred eighty-nine".