817968909 has 4 divisors (see below), whose sum is σ = 1090625216. Its totient is φ = 545312604.

The previous prime is 817968863. The next prime is 817968917. The reversal of 817968909 is 909869718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 817968909 - 2¹⁷ = 817837837 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 (817968929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136328149 + ... + 136328154.

It is an arithmetic number, because the mean of its divisors is an integer number (272656304).

Almost surely, 2^817968909 is an apocalyptic number.

It is an amenable number.

817968909 is a deficient number, since it is larger than the sum of its proper divisors (272656307).

817968909 is a wasteful number, since it uses less digits than its factorization.

817968909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272656306.

The product of its (nonzero) digits is 1959552, while the sum is 57.

The square root of 817968909 is about 28600.1557513242. The cubic root of 817968909 is about 935.2167261435.

The spelling of 817968909 in words is "eight hundred seventeen million, nine hundred sixty-eight thousand, nine hundred nine".