491256604609 has 3 divisors (see below), whose sum is σ = 491257305507. Its totient is φ = 491255903712.

The previous prime is 491256604589. The next prime is 491256604681. The reversal of 491256604609 is 906406652194.

The square root of 491256604609 is 700897.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 146302425025 + 344954179584 = 382495^2 + 587328^2 .

It is not a de Polignac number, because 491256604609 - 2¹³ = 491256596417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491256604109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 350449 + ... + 1051345.

It is an arithmetic number, because the mean of its divisors is an integer number (163752435169).

Almost surely, 2^491256604609 is an apocalyptic number.

491256604609 is the 700897-th square number.

491256604609 is the 350449-th centered octagonal number.

It is an amenable number.

491256604609 is a deficient number, since it is larger than the sum of its proper divisors (700898).

491256604609 is an frugal number, since it uses more digits than its factorization.

491256604609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1401794 (or 700897 counting only the distinct ones).

The product of its (nonzero) digits is 2799360, while the sum is 52.

The spelling of 491256604609 in words is "four hundred ninety-one billion, two hundred fifty-six million, six hundred four thousand, six hundred nine".