809735421609 has 9 divisors (see below), whose sum is σ = 1169621730589. Its totient is φ = 539821814700.

The previous prime is 809735421571. The next prime is 809735421643. The reversal of 809735421609 is 906124537908.

The square root of 809735421609 is 899853.

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

809735421609 is a `hidden beast` number, since 8 + 0 + 9 + 7 + 3 + 5 + 4 + 21 + 609 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 809735421609 - 2¹⁵ = 809735388841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (809735421109) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2549584 + ... + 2849534.

It is a 1-persistent number, because it is pandigital, but 2⋅809735421609 = 1619470843218 is not.

Almost surely, 2^809735421609 is an apocalyptic number.

809735421609 is the 899853-rd square number.

809735421609 is the 449927-th centered octagonal number.

It is an amenable number.

809735421609 is a deficient number, since it is larger than the sum of its proper divisors (359886308980).

809735421609 is an frugal number, since it uses more digits than its factorization.

809735421609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599908 (or 299954 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 54.

The spelling of 809735421609 in words is "eight hundred nine billion, seven hundred thirty-five million, four hundred twenty-one thousand, six hundred nine".