491816905 has 8 divisors (see below), whose sum is σ = 590320584. Its totient is φ = 393360000.

The previous prime is 491816893. The next prime is 491816921. The reversal of 491816905 is 509618194.

It can be written as a sum of positive squares in 4 ways, for example, as 148937616 + 342879289 = 12204^2 + 18517^2 .

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

It is not a de Polignac number, because 491816905 - 2⁷ = 491816777 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18565 + ... + 36445.

It is an arithmetic number, because the mean of its divisors is an integer number (73790073).

Almost surely, 2^491816905 is an apocalyptic number.

It is an amenable number.

491816905 is a deficient number, since it is larger than the sum of its proper divisors (98503679).

491816905 is a wasteful number, since it uses less digits than its factorization.

491816905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23387.

The product of its (nonzero) digits is 77760, while the sum is 43.

The square root of 491816905 is about 22176.9453487174. The cubic root of 491816905 is about 789.3467360318.

The spelling of 491816905 in words is "four hundred ninety-one million, eight hundred sixteen thousand, nine hundred five".