817243409 has 4 divisors (see below), whose sum is σ = 860256240. Its totient is φ = 774230580.

The previous prime is 817243331. The next prime is 817243439. The reversal of 817243409 is 904342718.

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 a cyclic number.

It is not a de Polignac number, because 817243409 - 2¹⁶ = 817177873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (817243439) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21506387 + ... + 21506424.

It is an arithmetic number, because the mean of its divisors is an integer number (215064060).

Almost surely, 2^817243409 is an apocalyptic number.

It is an amenable number.

817243409 is a deficient number, since it is larger than the sum of its proper divisors (43012831).

817243409 is a wasteful number, since it uses less digits than its factorization.

817243409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43012830.

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 817243409 is about 28587.4694402985. The cubic root of 817243409 is about 934.9401465875.

The spelling of 817243409 in words is "eight hundred seventeen million, two hundred forty-three thousand, four hundred nine".